Sources of International Law

CHAPTER 6 SOURCES OF INTERNATIONAL LAW CRAIG EGGETT, TAXIARCHIS FISKATORIS, MARKO SVICEVIC, VICTOR STOICA, RAFFAELA KUNZ, LUCAS CARLOS LIMA, AND BERNARDO MAGESTE CASTELAR CAMPOS INTRODUCTION CRAIG EGGETT BOX 6.1 Required Knowledge and Learning Objectives Required knowledge: Nature and Purpose of International Law; Approaches to International Law Learning objectives: Understanding the nature of sources in international law and the relationship between the sources. BOX 6.2 Interactive Exercises Access interactive exercises for this chapter1 by positioning your smartphone camera at the dot-filled box, also known as a QR code. Figure 6.1 QR code referring to interactive exercises. 1 https://openrewi.org/en-projects-project-public-international-law-sources-of-international-law/ 1 https://openrewi.org/en-projects-project-public-international-law-sources-of-international-law/ DOI: 10.4324/9781003451327-8 This chapter has been made available under a (CC-BY-SA) 4.0 license. 156 CRAIG EGGETT A. INTRODUCTION The topic of the ‘sources’ of international law is essentially concerned with one central, and rather basic, question: how are international legal rules made? Despite the foundational nature of this question, there are few areas of international legal scholarship that have generated such long-running and ferce debate. Questions about the sources of international law have always been central to international legal discourse, and understanding the language of the sources remains critical for all actors wishing to engage with the international legal system. This chapter introduces some broader questions about the sources of international law, with the aim of setting the scene for the examination of the individual sources discussed in the following chapters. B. THE CONCEPT OF A ‘SOURCE’ OF INTERNATIONAL LAW As a preliminary point, it is useful to consider the precise meaning of ‘source’, as some authors have used the term to describe a range of foundational aspects and processes of the international legal system. Some scholars have understood this term to cover the origins and rationale of international law as such.2 The use of the term ‘source’ to include the background and objectives of a rules-based international order is broader and rather unconventional.3 More commonly, sources doctrine is concerned with the processes through which international legal rules are created.4 These processes are, and should continue to be, subject to discussion and critique. As parts of the foundation of international law, they should be continually revisited to ensure they refect the modern objectives of the legal system. I. SOURCES AND THE INTERNATIONAL LEGAL SYSTEM The international legal system, like all legal systems, is composed of primary and secondary rules.5 Primary rules are those that create obligations, grant rights, or change a legal situation. Examples include the prohibition of the use of force, rules on human rights, and provisions that set conditions for membership to international organisations. Conversely, secondary rules are those that regulate the creation, modifcation, and application of those rules. Examples include rules on the interpretation of treaties and the law of State responsibility. The rules on the sources of international law are a category of secondary rules; they set out the criteria for the creation of other international rules. The presence and operation of secondary rules is indispensable for the existence and functioning of the international legal system. As such, when searching for answers to questions about the sources, it is 2 Percy Corbett, ‘The Consent of States and the Sources of the Law of Nations’ (1925) 6 BYIL 20, 29–30. 3 See, for example, Randall Lesafer, ‘Sources in the Modern Tradition: The Nature of Europe’s Classical Law of Nations’ in Samantha Besson and Jean d’Aspremont (eds), The Oxford Handbook on the Sources of International Law (OUP 2017). 4 Samantha Besson, ‘Theorizing the Sources of International Law’ in Samantha Besson and John Tasioulas (eds), The Philosophy of International Law (OUP 2010) 170. 5 Herbert Hart, The Concept of Law (OUP 1994) 94. S O U R C E S O F I N T E R N AT I O N A L L A W 157 necessary to confront difcult questions about the foundations of international law as a normative order. In turn, the theory and practice of the sources plays a role in shaping international law as a legal system. In other words, there is a co-constitutive and mutually infuential relationship between the sources of international law and the international legal system.6 Sources questions touch on issues such as the functions of diferent international actors, including the continued dominance of States as participants in the legal system, and the relationship between international legal norms. II. CATEGORIES OF SOURCES? There is a tendency to attempt to delineate between diferent categories of sources of international law. Most commonly, authors have distinguished between formal and material sources of law.7 The formal sources of international law provide criteria against which the validity of a prospective rule is to be judged. If these criteria are fulflled, there is a valid and legally binding rule of the system. An example is the procedure for the formation of a treaty as refected in the Vienna Convention on the Law of Treaties.8 Conversely, material sources do not in and of themselves create binding legal rules, but may provide evidence for the existence of such rules and their content. Examples include some resolutions of international organisations, the output of the International Law Commission (ILC), and judicial decisions.9 Others suggest a division between primary and secondary (or subsidiary) sources. This distinction is also drawn using the terms ‘formal’ and ‘material’ sources of law.10 Both sets of labels delineate between, on the one hand, the criteria for the creation of binding rules and, on the other, the evidence for the fulflment of such criteria. It should be noted with caution that the use of the terms ‘primary’ and ‘secondary’ sources in this way is distinct from the description of primary and secondary rules referred to above, which refers to categorisation of diferent functions of rules. It is also important to note that this use of primary and secondary should not be taken to imply a formal and strict hierarchy between the sources as may be implied from such use in other legal systems. The question of hierarchy between sources and norms is considered below. C. ARTICLE 38 ICJ STATUTE Article 38 of the Statute of the International Court of Justice (ICJ) is the traditional, and perhaps inevitable, starting point for an examination of the sources of international law. 6 Gleider Hernández, ‘Sources and the Systematicity of International Law: A Co-Constitutive Relationship?’ in Besson and d’Aspremont (n 3). 7 Malcolm Shaw, International Law (7th edn, CUP 2014) 51; Patrick Dailler, Mathias Forteau, and Alain Pellet, Droit International Public (8th edn, LGDJ 2009) 124–125. 8 Vienna Convention on the Law of Treaties (adopted 23 May 1969, entered into force 27 January 1980) 1155 UNTS 331; on the law of treaties, see Fiskatoris and Svicevic, § 6.1, in this textbook. 9 On sources beyond article 38 ICJ statute, see Kunz, Lima, and Castelar Campos, § 6.4, in this textbook. 10 For a critique of these terms, see Bhupinder Chimni, ‘Customary International Law: A Third World Perspective’ (2018) 112 AJIL 1. 158 CRAIG EGGETT As evidenced by the opening sentence, this provision is, strictly speaking, the lex arbitri (Latin: ‘applicable law’) provision of the ICJ. That being said, article 38 has traditionally been viewed as an authoritative statement of the sources of international law.11 This provision is composed of three main parts. First, article 38(1)(a)–(c) sets out the (formal or primary) sources of international law: treaties, customary international law, and general principles of law. Second, article 38(1)(d) sets out the ‘subsidiary means’ for the determination of international rules. Third, article 38(2) allows for the Court to resolve a dispute before it on the basis of (a form of) equity, should the parties agree. On the traditional understanding of international law, States play the dominant role in the formation of international rules and an initial reading of article 38 seems to confrm this. Indeed, the mainstream view has traditionally been that States are not bound by international rules unless they have consented to them.12 While it is clear that States remain prominent actors in international law-making,13 it can now be legitimately questioned whether the creation of rules remains the sole prerogative of States. Article 38(1)(d)’s reference to ‘subsidiary means’ refects the aforementioned distinction between formal and material sources. These ‘means’ are not sources of binding rules themselves but can provide evidence that the conditions set out in (one of the) formal sources have been fulflled. This is confrmed by the reference to article 59 ICJ statute, which states that the decisions of the Court have ‘no binding force except between the parties and in respect of that particular case’. As will be explained below, that judicial decisions are not generally binding as such does not mean that the jurisprudence of international courts and tribunals does not play an important role in shaping the international legal system. The reference to ex aequo et bono (Latin: ‘according to the right and the good’) in article 38(2) identifes the possibility that a dispute before the Court may be settled on the basis of equitable considerations, should the parties agree. This is a reference to a specifc form of equity free from interaction with legal norms.14 To date, this provision has never been invoked before the ICJ. Article 38 ICJ Statute has long been revered as an authoritative statement of the sources of international law. While it is clear that this provision is central to any doctrine sources, it should not be read in isolation. It is important to both question what is generally accepted as part of the mainstream position on the sources15 and to consider what international law-making looks like beyond the text of article 38.16 11 Gleider Hernández, The International Court of Justice and the Judicial Function (OUP 2014) 31; Godefridus van Hoof, Rethinking the Sources of International Law (Kluwer 1983) 82. 12 On consent, see Gonzàlez Hauck, § 2.2, in this textbook. 13 On States as main subjects of international law, see Green, § 7.1, in this textbook. 14 For an overview, see Vaughn Lowe, ‘The Role of Equity in International Law’ (1989) 12 AYIL 54. 15 See, for example, the contributions of Mónica García Salmones-Rovira and Upendra Baxi regarding the ‘antiformalist tradition’ in Besson and d’Aspremont (n 3). 16 For an excellent overview of the multifaceted nature of international law-making, see Christine Chinkin and Alan Boyle, The Making of International Law (OUP 2007). S O U R C E S O F I N T E R N AT I O N A L L A W 159 D. HIERARCHY IN THE SOURCES OF INTERNATIONAL LAW At frst sight, it may appear that the sources listed in article 38(1)(a)–(c) ICJ Statute are listed in a specifc order, denoting a hierarchy between them. This is not the case. There can be multiple rules that have similar or identical content, but emanate from diferent sources of international law. For example, in the Nicaragua case, the Court confrmed the parallel existence of customary and treaty rules regarding the use of force.17 This question of a hierarchy between the sources is separate from that of hierarchical relationships between international norms. While there are clear examples of normative hierarchies, a rule will not prevail over another because of its source. The question of a hierarchy between the sources is also separate from the question of the role and importance of the diferent sources of international law more generally. For example, much of international law-making is done by States through concluding treaties. There are now thousands of bilateral and multilateral treaties covering a broad range of topics. Conversely, it may be possible to argue that many of the fundamental rules of general application are custom or general principles. Broadly speaking, there are three aspects of international law that are referred to as evidence of hierarchical relationships between norms: article 103 UN Charter,18 jus cogens (Latin: ‘peremptory norms’) and obligations erga omnes (Latin ‘towards all’). It may be argued that article 103 UN Charter functions as a ‘supremacy clause’, elevating the Charter to a hierarchically superior position in the international legal system.19 While at frst sight this seems to be the case, it should be noted that the practical efect of this provision is largely limited to the obligation to comply with UN Security Council resolutions contained in article 25, as there are few other specifc and concrete obligations in the Charter. It should also be borne in mind that this provision functions more as a rule of precedence, very diferent to the consequences of a norm’s jus cogens status, for example. Jus cogens norms are clear example of hierarchy in international law. These peremptory rules of international law are defned as rules ‘from which no derogation is permitted’.20 In the event of a confict between a rule of jus cogens and another international rule, the jus cogens rule prevails and the other rule is void.21 Further, articles 40 and 41 of ARSIWA impose additional obligations on States in the event of serious violations of jus cogens norms,22 including a requirement to cooperate to bring about the end of the 17 Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v United States of America) (Merits) [1986] ICJ Rep 14 [178]. 18 Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI. 19 Dinah Shelton, ‘International Law and “Relative Normativity”’ in Malcolm Evans (ed), International Law (4th edn, OUP 2014) 157. 20 VCLT 1969 (n 10) article 53. 21 Ibid articles 53 and 64. 22 ILC, ‘Responsibility of States for Internationally Wrongful Acts (53rd session 23 April–1 June and 2 July–10 August 2001) UN Doc A/RES/56/83 Annex. 160 CRAIG EGGETT jus cogens violation and an obligation not to recognise as lawful any situation created as a result of such a violation. Established jus cogens norms include the prohibitions on genocide, slavery, torture, and racial discrimination.23 Obligations erga omnes are defned as those owed ‘towards the international community as a whole’, with the result that ‘all States can be held to have a legal interest in their protection’.24 This seems to confrm the importance of such obligations, yet this concept does not imply a hierarchy between these and other norms. The label ‘erga omnes’ serves to denote only an expansion in potential scope of actors who can invoke violation of the rule. This is a purely procedural device, which facilitates the enforcement of international rules which may not necessarily involve an injured State or to increase the likelihood of enforcement of rules deemed to be substantively important.25 Obligations erga omnes do not prevail over other rules of international law in the same way as jus cogens rules. E. CONCLUSION This chapter has explored the foundations of the doctrine of the sources in international law. In doing so, it has explained that the primary objective of this doctrine is to distinguish between rules that are part of the corpus of international law and those that are not. It has been explained that article 38 ICJ Statute constitutes an essential starting point for an account on the sources of international law, yet it does not paint a full picture. The relationships between international norms and their sources are complex and will be taken up further in subsequent chapters. BOX 6.3 Further Reading Further Reading · S Besson and J d’Aspremont, The Oxford Handbook of the Sources of International Law (OUP 2017). · C Chinkin and A Boyle, The Making of International Law (OUP 2007). · H Thirlway, The Sources of International Law (OUP 2014). §§§ 23 See, generally, the ILC’s work on the topic: ILC, ‘Fourth Report on Peremptory Norms of General International Law (Jus Cogens) by Dire Tladi, Special Rapporteur’ 71st Session (29 April–7 June and 8 July–9 August 2019) UN Doc A/CN.4/727. 24 Barcelona Traction, Light and Power Company Limited (Belgium v Spain) (Preliminary Objections, Second Phase) [1970] ICJ Rep 3 [33]. 25 Shelton (n 19) 140. S O U R C E S O F I N T E R N AT I O N A L L A W 161 § 6.1 TREATY LAW TAXIARCHIS FISKATORIS AND MARKO SVICEVIC BOX 6.1.1 Required Knowledge and Learning Objectives Required knowledge: History of International Law; Consent; Subjects and Actors; States Learning objectives: Being able to define the term ‘treaties’ as sources of international law; being familiar with the key characteristics of treaties and how they are negotiated, drafted, and interpreted; understanding how treaties enter into force, and, conversely, how they are terminated or invalidated, and understanding what reservations are. A. INTRODUCTION Article 38(1) of the Statute of the International Court of Justice (ICJ) names ‘conventions, whether general or particular, establishing rules expressly recognized by . . . states’ as the frst source of public international law. More commonly known as ‘treaties’, they represent the most trusted and least controvertible avenue for States to express their consent to international legal rules.26 The United Nations (UN) Treaty Collection, which registers and publishes lists of treaties in accordance with article 102 of the UN Charter, records over 250,000 treaties.27 The basic international instrument of treaty law is the 1969 Vienna Convention on the Law of Treaties (VCLT), which is the focus of this chapter.28 This chapter will therefore defne what treaties are, how they are negotiated and drafted, how they may be invalided or terminated, and how they are to be interpreted. As of March 2023, the VCLT has been ratifed by 116 States.29 Most of its provisions have codifed pre-existing customary international law, while other provisions have generated new custom.30 The VCLT only ‘applies to treaties between States’ (article 1). 26 Statute of the International Court of Justice (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI. On consent, see González Hauck, § 2.2, in this textbook. 27 See United Nations Treaty Collection <https://treaties.un.org/pages/overview.aspx?path=overview/overview/ page1_en.xml> accessed 8 August 2023. See also article 102, Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS XVI. 28 Vienna Convention on the Law of Treaties (adopted 23 May 1969, entered into force 27 January 1980) 1155 UNTS 331 (VCLT). 29 United Nations Treaty Series, Vienna Convention on the Law of Treaties <https://treaties.un.org/Pages/ showDetails.aspx?objid=080000028003902f&clang=_en> accessed 9 August 2023. 30 Rudolf Bernhardt, ‘Treaties’ in Rudolf Bernhardt (ed), Encyclopedia of Public International Law (7th edn, Elsevier Science Publishers 1984) 459, B.V. 162 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C The rules regulating treaties between States and international organisations, and between international organisations have also been imprinted in a convention, which has not yet entered into force.31 A third international convention with direct relevance to treaty law is the Vienna Convention on Succession of States in Respect of Treaties, which is in force but poorly ratifed.32 All three have been drafted by the International Law Commission (ILC). The ILC is also responsible for several non-binding instruments which contribute to the overall study and scope of the law of treaties, such as the 2011 ‘Draft Articles on the Efects of Armed Conficts on Treaties’,33 the 2016 ‘Draft Conclusions on Subsequent Agreements and Subsequent Practice in Relation to the Interpretation of Treaties’,34 and the 2017 ‘Draft Guide to Provisional Application of Treaties’.35 B. THE NATURE AND CHARACTER OF TREATY LAW I. TREAT Y LAW IN CONTEXT AND OF THE TIMES Treaty law forms part and parcel of the ‘nuts and bolts’ of international law. As such, it is interwoven with almost every feld of international law. For example, while treaties are traditionally concluded between States, the role of non-State actors, broadly speaking, has increasingly brought about new questions. Non-governmental organisations,36 although without legal capacity to conclude treaties, have, and continue to play, a growing role in the drafting and negotiating of treaties.37 Likewise, as entities capable of legal personality, questions arise as to what extent non-governmental organisations derive obligations under treaty law, such as universal and regional human rights treaties. It is also worth noting that treaty law, although its progressive development and codifcation enhances clarity, is not without controversy and ambiguity. Worthy of recollection is the fact that at the time the VCLT was negotiated and eventually adopted, not all States we see today were independent. Any consideration of the VCLT 31 UNGA ‘Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations’ (adopted 21 March 1986, not yet in force) UN Doc A/CONF.129/15 (‘VCLTIO’). 32 Vienna Convention on Succession of States in Respect of Treaties (adopted 23 August 1978, entered into force 6 November 1996) 1946 UNTS 3. 33 ILC, ‘Draft Articles on the Efects of Armed Conficts on Treaties’ (2011) II(2) U.N.Y.B.I.L.C. 107. 34 ILC, ‘Draft Conclusions on Subsequent Agreements and Subsequent Practice in Relation to the Interpretation of Treaties’ (2018) II(2) U.N.Y.B.I.L.C. 24. 35 ILC, ‘Draft Guidelines and Draft Annex Constituting the Guide to Provisional Application of Treaties’ in (2021) II(2) U.N.Y.B.I.L.C. 36 On non-governmental organisations, see He Chi, § 7.6, in this textbook. 37 See for example Maiara Giorgi, ‘The Role of Non-Governmental Organizations in the Process of International Treaty Making’ (2019) 19 AMDI 153; Kal Raustiala, ‘NGOs in International Treaty-Making’ in Duncan B Hollis (ed), The Oxford Guide to Treaties (2nd edn, OUP 2020) 173. S O U R C E S O F I N T E R N AT I O N A L L A W 163 as a treaty regulating other treaties must therefore bear in mind its historical context. By this token, it has been pointed out that applying a purely positivist approach to the VCLT would marginalise its role in international law.38 These difcult issues more often than not transcend the VCLT itself, plaguing by extent the entirety of the law of treaties. Consider for example the efect of treatymaking before the era of human rights and the adoption of the VCLT. The partitioning of Africa was in many ways efected through treaty law. Despite what were in fact treaties which ultimately laid claim to territory and to the detriment of peoples of that territory, they were not necessarily directed at the various peoples they were negotiated with, but rather as ‘legal’ symbols against rival European powers.39 While it is oftentimes easy to dismiss these practices and the corresponding efects of treaty law as relegated to the pages of history, the potential for these efects remains today.40 Indeed, while a fundamental principle of treaty law is that treaties are to be negotiated and implemented in good faith, there remain numerous cases even today where the law of treaties has fallen short of this expectation. II. DEFINING TREATIES Article 2(1)(a) VCLT defnes a treaty as ‘an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation’ (article 2(1)(a) VCLT). 1. An International Agreement Concluded Between States ‘Every State possesses capacity to conclude treaties’.41 Although reference is made in the VCLT exclusively to States, the defnition of treaties extends to international organisations.42 Until such a time as the 1986 VCLTIO enters into force, which is admittedly very similar to the VCLT, such treaties are based on other sources of international law, in particular customary international law.43 Of course, it is not States as such but their representatives that conclude treaties. In order to be able to legally and validly do so, the State must have provided them with a document bestowing ‘full powers’ (article 2(1)(c) VCLT). Such a document is unnecessary for heads of State, heads of government, ministers of foreign afairs, and 38 See e.g. European Commission for Democracy Through Law, ‘Human Rights Treaties and the Vienna Convention on the Law of Treaties – Conficts or Harmony’ (7–8 October 2005, Coimbra) CDL-UD(2005)014rep. 39 Saadia Touval, ‘Treaties, Borders and the Partition of Africa’ (1966) 7(2) JAH 280. 40 Baron FM van Asbeck, ‘International Law and Colonial Administration’ (1953) 39 Transactions of the Grotius Society 5, 8. See also broadly, Antony Anghie, ‘The Evolution of International Law: Colonial and Postcolonial Realities’ (2006) 27(5) TWQ 739. 41 Article 6 VCLT. 42 On international organisations, see Baranowska, Engström, and Paige, § 7.3, in this textbook. 43 Alina Kaczorowska, Public International Law (4th edn, Routledge 2010) 89–90. See also article 3(b) VCLT. 164 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C on specifc occasions for other high-ranking State representatives, such as heads of diplomatic missions (article 7(2) VCLT). A State may exceptionally endorse and validate the acts of an unauthorised representative ex post facto (article 8 VCLT). 2. In Written Form For an international agreement to be called a treaty, it must be in written form, but not necessarily on paper. This is exactly the feature that renders treaties the most predictable and hence reliable source of public international law. Oral international agreements are not treaties as per the VCLT, but they may still have legal efects.44 3. Whether Embodied in a Single Instrument or in Two or More Related Instruments Treaties are usually contained in a single document, but they do not need to be. Exchange of letters (diplomatic notes), and even records of meetings between State representatives may constitute treaties if the intention of the parties was to create through them binding efects under international law.45 4. Governed by International Law The intention to establish obligations and/or rights under international law is a key requirement. States (and international organisations) are free to sign contractual agreements governed by national law (e.g. for leasing an embassy’s premises), which cannot be considered treaties. They are also free to enter international agreements not giving rise to obligations and/or rights under international law. Such agreements are often called ‘Memoranda of Understanding’ (MoUs). However, one should not pay too much attention to the headline of an agreement, as MoUs may be proper treaties if the intention of the parties to give them binding efect under international law can be discerned. This intention must be manifest within the text and context of the treaty. 5. Whatever Its Particular Designation If an international agreement fulfls the above four characteristics, it is a treaty from a legal point of view, whatever its name. Some of the most common names attached to a treaty are ‘convention’, which is usually the name given to treaties prepared within an international organisation (e.g. UN Convention on the Law of the Sea; European Convention on Human Rights); ‘protocol’, which is in most cases a treaty that supplements a pre-existing treaty with additional rights or obligations (e.g. Additional Protocols to the 1949 Geneva Conventions on International Humanitarian Law); ‘charter’, which is the label preferred for the constitutive treaties of international organisations (e.g. UN Charter); the term may also designate a document setting 44 Article 3 VCLT; article 3 VCLTIO and Anthony Aust, ‘Vienna Convention on the Law of Treaties (1969)’ Max Planck Encyclopedia of International Law (March 2023) para 12. See also broadly, Kelvin Widdows, ‘On the Form and Distinctive Nature of International Agreements’ (1981) 7(1) Aust YBIL 114. 45 See Jan Klabbers, ‘Qatar v. Bahrain: The Concept of “Treaty” in International Law’ (1995) 33(3) AdV 361. S O U R C E S O F I N T E R N AT I O N A L L A W 165 out rights or privileges (e.g. EU Charter of Fundamental Rights, African Charter on Humans and Peoples’ Rights); and the treaty establishing an international court or tribunal is often called a ‘statute’ (e.g. ICJ Statute; ICC Statute). The word ‘covenant’ originates in religious scripts and traditionally refers to a solemn promise to engage in or refrain from a specifed action. In international law it is used in the title of two major human rights conventions: International Covenant on Civil and Political Rights (ICCPR) and the International Covenant on Economic, Social and Cultural Rights (ICESCR).46 The label ‘pact’, more common during the interwar period, seems to connote a deal, that is not only legally but also morally binding (e.g. 1928 Kellogg-Briand Pact for Renunciation of War as an Instrument of National Policy). Finally, the term ‘agreement’ is used as an umbrella term covering both treaties and other instruments not meeting the VCLT criteria. In a narrow sense, an agreement is usually employed for treaties of a technical or administrative character. III. CLASSIFICATION OF TREATIES Treaties establishing mutual rights and obligations between two parties are classifed as bilateral. The great bulk of international treaties are bilateral in nature, with extradition treaties being one example.47 A multilateral treaty is, on the other hand, a binding international agreement between many parties.48 A treaty between more than two but still not many parties can also be classifed as plurilateral. Most bilateral and plurilateral treaties merely create mutual rights and/or obligations for their parties, similarly to typical contracts of domestic law (contractual treaties). Although multilateral treaties also establish binding rights and/or obligations, most of them may eventually create, modify, elucidate, and stabilise, or progressively develop international law more generally (law-making treaties).49 To be sure, several multilateral treaties purport to do so. The distinction between ‘contractual treaties’ and ‘law-making treaties’ is not always obvious. IV. OBSERVANCE AND APPLICATION OF TREATIES The whole branch of international treaty law is premised on the fundamental legal principle of pacta sunt servanda (Latin: ‘agreements must be respected’). Article 26 VCLT enunciates that ‘[e]very treaty in force is binding upon the parties to it and must be 46 International Covenant on Civil and Political Rights (adopted 16 December 1966, entered into force 23 March 1976) 999 UNTS 171; International Covenant on Economic, Social and Cultural Rights (adopted 16 December 1966, entered into force 3 January 1976) 999 UNTS 3. 47 E.g. Extradition Treaty Between the Argentine Republic and the Republic of Peru (11 June 2004) 2446 UNTS 259. 48 See e.g. the African Charter on Human and Peoples’ Rights (adopted 27 June 1981, entered into force 21 October 1986) 1520 UNTS 217. 49 See Catherine Brölmann, ‘Law-Making Treaties: Form and Function in International Law’ (2005) 74 Nordic Journal of International Law 383. 166 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C performed by them in good faith’. A change of government does not release the State from its treaty obligations, unless the new government can raise a valid ground for the termination of the treaty, as discussed below. Besides, ‘[a] party may not invoke the provisions of its internal law as justifcation for its failure to perform a treaty’ (article 27 VCLT). The fip side to that is the principle pacta tertiis nec nocent nec prosunt (Latin: ‘agreements neither injure nor beneft third parties’). This is enshrined in article 34 VCLT, according to which a ‘treaty does not create either obligations or rights for a third State without its consent’. When parties to a treaty intend to impose an obligation on third parties, the latter must accept the obligation in writing (article 35 VCLT). If a treaty provision acquires the status of a customary rule of international law, it then becomes binding on third parties, even without their expressed consent.50 The question of whether treaties are directly binding on individuals or other non-State actors is of marked importance in the context of international human rights law and international criminal law, but has yet to be doctrinally settled.51 Finally, unless otherwise agreed by their parties, treaties do not apply retroactively.52 C. TREATY-MAKING I. DRAFTING AND NEGOTIATION Before adopting a bilateral treaty, States normally hold a series of meetings of diplomats and legal experts who negotiate and draft the terms of the treaty. Multilateral treaties, especially ‘law-making treaties’, are negotiated at international conferences, usually summoned by international organisations. At international conferences, where negotiations are more difcult due to the number of participants, States often debate based on optional draft texts prepared by committees of experts, such as the ILC. The drafting process of a treaty may take many years. States are free to decide the place, time frames, setup, and rules of procedure of a conference. The VCLT only stipulates that, unless participants decide otherwise, the minimum requirement for the adoption of the text of a treaty at an international conference is a two-thirds majority of the ‘States present and voting’.53 In practice, States resort to voting only if consensus appears impossible. II. SIGNATURE Successful negotiations conclude with the adoption of the text of the treaty and its recognition as authentic and defnitive.54 The most common way for authenticating 50 See article 38 VCLT; on customary international law, see Stoica, § 6.2, in this textbook. 51 See Christine Chinkin, Third Parties in International Law (OUP 1993); Marko Milanović, ‘Is the Rome Statute Binding on Individuals? (And Why We Should Care)’ (2011) 9 JICJ (2011) 21. 52 Article 28 VCLT. 53 Article 9(2) VCLT. 54 Article 10 VCLT. S O U R C E S O F I N T E R N AT I O N A L L A W 167 the fnalised text of a treaty is its signature. Signing a treaty is an expression of a government’s intention to render the treaty binding for its State in due course. Nonetheless, the signature alone seldom establishes the consent of States to be bound by the treaty and an additional step is required (see next section).55 Binding agreements from the point of signature are called ‘treaties in simplifed form’ or ‘executive agreements’. They mostly concern bilateral matters of technical nature or of minor importance. It is still debated whether such treaties are legally or politically binding. Ordinarily, it is evident from the text of the treaty when no further steps are required. The signature entails the legal obligation of the signatory ‘to refrain from acts which would defeat the object and purpose of a treaty’ until the ratifcation of the treaty, or until the signatory ‘shall have made its intention clear not to become a party to the treaty’ (article 18 VCLT). This interim obligation is vague and open to contradictory interpretations.56 III. CONSENT TO BE BOUND As a matter of rule, States establish on the international plane their consent to be bound by a treaty through the acts of ‘ratifcation’, ‘acceptance’, ‘approval’, or ‘accession’, although ‘any other [agreed] means’ are an option (articles 2(1)(b) and 11 VCLT). A second step after signature ofers the required time to reconsider the treaty, eventually to submit it to parliamentary scrutiny and approval, or to enact respective legislation. It may take many years between signature and ratifcation, as there are no general time limits, unless the treaty specifes them. After all, States are under no obligation to ratify a treaty that they have signed. Ratifcation of bilateral treaties occurs through the exchange of documents called ‘instruments of ratifcation’, which are issued by the competent authorities of the contracting States. A mere mutual notifcation of completion of all domestic procedures that give efect to the treaty may in routine cases replace the ceremonial exchange of instruments. Treaties remain commonly open for signature until an arranged date. States that did not exist or sign the treaty before that date can still adhere to the treaty if the treaty or its parties allow it.57 The international act with which a State avails itself of the opportunity to become a party to a treaty previously adopted by another is called ‘accession’. It consists of an expression to be bound by a treaty and hence has the same legal efect as ratifcation.58 It usually happens after the treaty has entered into force, but, depending on the treaty, it can also take place before. 55 Article 12 VCLT. 56 See Paul Gragl and Malgosia Fitzmaurice, ‘The Legal Character of Article 18 of the Vienna Convention on the Law of Treaties’ (2019) 68(3) ICLQ 699. 57 Article 15 VCLT. 58 See article 2(1) VCLT. 168 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C BOX 6.1.2 Advanced: Acceptance, Approval The acts of ‘acceptance’ and ‘approval’ equally establish at the inter-State level the consent of States to assume treaty obligations and rights. In other words, they do not differ from ‘ratification’ from a legal perspective. Their difference is basically one of preferred terminology, the terms ‘acceptance’ and ‘approval’ being mostly used by States without a constitutional duty of treaty ratification. Besides, some constitutions provide for the possibility to accept a treaty by a mere executive action, before all domestic procedures for a formal ratification have been completed. When international organisations express their consent to be bound by a treaty, the term ‘act of formal confirmation’ replaces the word ‘ratification’. Ratifcation, acceptance, approval, or accession of multilateral treaties is accomplished with the deposit of the respective instruments with the depositary.59 The depositary is one or more States, an international organisation, or the secretary-general of an international organisation, especially the UN.60 The depositary is normally designated by the treaty, among others to keep custody of the original text of the treaty, to collect all documents or communications relating to it, and inform respectively all parties concerned.61 IV. ENTRY INTO FORCE Ratifcation does not signify an immediate assumption of the obligations and/or rights emanating from the treaty, which only begins when the treaty enters into force. After the ratifcation and before the entry of the treaty into force, States must still ‘refrain from acts which would defeat the object and purpose of a treaty’, provided that such entry into force is not unduly delayed (article 18(b) VCLT). Although it is very infrequent, States that have ratifed a treaty may freely withdraw their consent to be bound before the treaty becomes operative. There may also be transitional clauses, dealing for instance with the permissibility of reservations, that take efect from the adoption of the treaty, as discussed below. Most treaties contain a clause specifying when and how they will come into force.62 59 60 61 62 Article 16 VCLT. Article 76 VCLT. Articles 76–79 VCLT. See for example article 110(2) UN Charter. E.g. article 308(1) UN Convention on the Law of the Sea: ‘This Convention shall enter into force 12 months after the date of deposit of the sixtieth instrument of ratifcation or accession’. S O U R C E S O F I N T E R N AT I O N A L L A W 169 BOX 6.1.3 Advanced: Entry Into Force Clauses Although there are several variations, such clauses typically stipulate a minimum number of ratifications (and sometimes accessions) necessary to trigger the entry into force. Some of them contain additional conditions, such as a list of specific States that must figure on the ratifications table, or an additional short period of time to elapse after the last required ratification. In absence of such a clause and of a related agreement by the signatories, the treaty cannot take effect before all of them have ratified it. This is to guarantee a certain degree of reciprocity. Bilateral treaties often enter into force at the time the two parties exchange the ratifcation instruments, while treaties in simplifed form can readily come into force immediately after signature. In case of an accession, the treaty enters into force for the acceding party on the date of the deposit of the accession instrument, or after a short period of time, if there was a corresponding provision with respect to the initial entry into force of the treaty.63 V. REGISTRATION AND PUBLICATION Article 102 UN Charter requires that ‘every treaty and every international agreement entered into by any Member of the United Nations . . . shall as soon as possible be registered with the Secretariat and published by it’. Registration and publication with the UN Treaty Series is meant to eradicate the confictual dynamic of secret diplomacy and to enable public access. The UN Charter warns that unregistered international agreements cannot be invoked before any organ of the UN, including the ICJ (article 102(2)). However, the practice of UN organs is less strict than the rule. Registration should not be confused with a deposit of a ratifcation instrument with the UN Secretary-General. Treaties and international agreements can only be registered with the UN after their entry into force. The registration and publication duty extends to cases of treaty amendments. The registration by just one party to the treaty is adequate, while multilateral treaties are registered by their depositary.64 The UN does not impose any time constraints for registration. More importantly, ‘non-registration or late registration . . . does not have any consequence for the actual validity of the agreement, which remains no less binding upon the parties’.65 Vice versa, the act of registration cannot turn a non-binding international agreement into a binding treaty. 63 Article 24(3) VCLT. 64 Article 77 VCLT; on the institution of the ‘depositary’ see supra C.III. 65 Case Concerning Maritime Delimitation and Territorial Questions between Qatar and Bahrain (Qatar v Bahrain) (Jurisdiction and Admissibility) [1994] ICJ Rep 112 para 29. 170 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C VI. ALTERATIONS 1. Amendments An amendment is a change of one or more treaty provisions, usually with the aim of updating or enhancing the treaty regime. Given that amendments afect all parties to the treaty, they must obtain the consent of parties to be bound by the amended provision. Thus, amendments are negotiated, signed, ratifed, brought into force, registered, and published. Some treaties require unanimity for an amendment to pass. If amendments can pass with a majority, parties that do not express their consent to be bound by the amendment remain bound by the previous provision, in conformity with the principles pacta tertiis nec nocent nec prosunt and pacta sunt servanda.66 However, new parties acceding the treaty must accept the treaty as amended.67 Between the parties that have ratifed the amendments or acceded the amended treaty, and those that have not ratifed them, it is the old provision that remains efective. The more parties to a treaty, the more difcult its amendment. This is why many multilateral treaties lay down specifc amendment procedures and requirements, which may deviate from the above canon. 2. Reviews and Revisions Some treaties provide an alternative ‘review’ or ‘revision’ procedure, which refers to updating the whole or parts of the treaty at a new diplomatic conference with the participation of all parties. Review or revision takes place after a provided number of years, or following a majority vote.68 3. Modifications Furthermore, ‘two or more of the parties to a multilateral treaty may conclude an agreement to modify the treaty as between themselves alone if: (a) the possibility of such a modifcation is provided for by the treaty; or (b) . . . not prohibited by the treaty’ (article 41 VCLT). The original treaty provisions remain applicable between those few parties and all other parties. The modifcation must not afect the rights and/or rights of other parties under the treaty, and must not be incompatible with the object and purpose of the treaty as a whole.69 D. TERMINATION AND INVALIDITY OF TREATIES I. TERMINATION AND SUSPENSION A treaty may be terminated or suspended in several situations. The termination permanently releases the parties from any obligation to perform the treaty.70 The 66 67 68 69 70 Article 40(4) VCLT. Article 40(5) VCLT. See for instance article 109 UN Charter or article 123 ICC Statute. Article 41 VCLT. Articles 70 and 72 VCLT. S O U R C E S O F I N T E R N AT I O N A L L A W 171 suspension releases them from their treaty obligations temporarily. However, the termination ‘does not afect any right, obligation or legal situation of the parties created through the execution of the treaty prior to its termination’ (article 70(1)(b) VCLT). It is also immaterial when there exists a parallel customary rule of international law, which continues being biding on States. Besides, ‘[d]uring the period of the suspension the parties shall refrain from acts tending to obstruct the resumption of the operation of the treaty’ (article 72(2) VCLT). 1. Consent Based A treaty may be terminated or suspended with the consent of all its parties.71 Likewise, if all parties to a treaty adopt a new substitute treaty, the earlier treaty impliedly loses its efect.72 However, the old treaty remains efective if not all its parties adhere to the new one. Should only some of the parties no longer intent to be bound by a treaty, they may denounce it or withdraw from it, but only if such a possibility is expressly allowed, implied by the nature of the treaty, or predicated on the established consensual intention of the parties.73 In any event, a party wishing to exit a treaty must give notice of its intention at least one year in advance.74 The term ‘denunciation’ is mostly used with reference to bilateral treaties, whereas ‘withdrawal’ usually describes the retreat from a multilateral treaty, which continues being in force among the rest of its parties. There is also the possibility that the treaty itself contains an expiration date, or a clear goal, the achievement of which terminates the agreement. Nonetheless, a treaty does not terminate merely because it has not reached the required ratifcations number for its entry into force.75 2. After a Material Breach of the Treaty The operation of a treaty can also be terminated or suspended because of its material breach. The VCLT defnes a material breach as ‘(a) a repudiation of the treaty not sanctioned by the present Convention; or (b) the violation of a provision essential to the accomplishment of the object or purpose of the treaty’ (article 60(3) VCLT). A material breach, regardless of its gravity, does not in itself terminate or suspend the treaty. It only entitles innocent parties to pursue the termination or suspension of the treaty in whole or in part, in accordance with a predetermined procedure.76 The consequences of a material breach depend on the bilateral or multilateral nature of the treaty.77 A breach of a multilateral treaty is more probable to temporarily render 71 72 73 74 75 76 77 Articles 54 and 57 VCLT. Article 59 VCLT. See article 56 VCLT. Article 56(2) VCLT. Article 55 VCLT. Articles 60 and 65–68 VCLT. Article 60 VCLT. 172 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C the treaty inefective between the injured and the defaulting State, rather than lead to a comprehensive termination of the treaty. The party that breached the treaty cannot invoke its own wrongdoing to terminate or suspend the treaty. Neither can a party pursue the termination or suspension of a treaty invoking the material breach of another treaty.78 Besides, ‘treaties of a humanitarian character’, including human rights treaties, cannot be terminated or suspended on such grounds (article 60(5) VCLT). If a material breach of a treaty causes harm to a State, secondary rules of State responsibility apply, irrespective of whether the harmed State pursues the termination or suspension of the breached treaty.79 3. Due to a Fundamental Change of Circumstances On demand of several drafting States, the VCLT did not exclude the termination of or withdrawal from a treaty due to a fundamental change of circumstances which has rendered the execution of treaty obligations unexpectedly onerous or unfair. However, to keep it in line with the primordial principle of the sanctity of treaties (pacta sunt servanda), the VCLT sets a high threshold for the application of the so-called rebus sic standibus (Latin: ‘so long as things stand’) clause.80 The ICJ has also consistently upheld a very restrictive approach.81 Such a pleading can only be made if cumulatively (1) the change is fundamental; (2) could not have been foreseen; (3) has ‘radically’ transformed the extent of obligations still to be performed under the treaty into something diferent from what originally agreed; and (4) the specifc circumstances at the time of the conclusion of the treaty constituted an essential basis of the consent of the parties to be bound by the treaty. Additionally, this ground of termination is inapplicable to treaties establishing a boundary. ‘A boundary established by treaty thus achieves a permanence which the treaty itself does not necessarily enjoy’.82 It is furthermore unavailable to any party that induced the fundamental change by not performing its duties towards the other treaty parties.83 4. Due to Supervening Impossibility of Performance A less controversial ground for termination/withdrawal is ‘the permanent disappearance or destruction of an object indispensable for the execution of the treaty’, which unexpectedly renders its performance not simply onerous or unfair, but impossible.84 If the supervening impossibility of performance is temporary, it can only lead to the suspension of the treaty. 78 79 80 81 82 Case Concerning the Gabčíkovo-Nagymaros Project (Hungary v Slovakia) (Merits) [1997] ICJ Rep 7 para 106. On State responsibility, see Arévalo-Ramírez, § 9, in this textbook. Article 62 VCLT. Gabčíkovo-Nagymaros (n 52) para 104. Case Concerning the Territorial Dispute (Libyan Arab Jamahiriya v Chad) (Merits) [1994] ICJ Rep 6 para 73; see also article 11 Vienna Convention on Succession of States in Respect of Treaties. 83 Article 62(2) VCLT. 84 Article 61(1) VCLT. S O U R C E S O F I N T E R N AT I O N A L L A W 173 Once again, if a party contributed to the occurrence of such a situation, it cannot itself pursue the termination/suspension of the treaty on this ground.85 The submergence of an island under the sea level, or the natural desiccation of a river as an efect of climate change, may be scenarios giving rise to such a termination/suspension ground. 5. Armed Conflicts The VCLT sets forth that [t]he severance of diplomatic or consular relations between parties to a treaty does not affect the legal relations established between them by the treaty except insofar as the existence of diplomatic or consular relations is indispensable for the application of the treaty. (article 63 VCLT) However, the efects of armed conficts on treaties fall outside the scope of the Convention.86 The ILC has attempted, to prepare a set of non-binding Draft Articles on the matter.87 The general principle is that the outbreak of an international armed confict, or a non-international armed confict in which governmental authorities take part, may terminate or suspend a treaty as between States parties to the confict or as between a State party to the confict and a State that is not – but not necessarily.88 However, there are a number of treaties, ‘the subject matter of which involves an implication that they continue in operation, in whole or in part, during armed confict’.89 Such are, by way of illustration, multilateral ‘law-making treaties’, treaties creating permanent regimes, especially treaties establishing boundaries, treaties for the international protection of human rights, treaties on international criminal justice, treaties relating to the international protection of the environment or to international watercourses and aquifers, treaties creating international organisations, treaties relating to diplomatic and consular relations, treaties relating to the international settlement of disputes, and of course treaties regulating the conduct of hostilities.90 6. Other Grounds Article 64 VCLT foresees an additional termination ground, namely the emergence of a new peremptory norm of general international law (jus cogens).91 In such an event, ‘any existing treaty which conficts with that norm becomes void and terminates’ (articles 64 and 44(3) VCLT). 85 Article 61(2) VCLT. 86 Article 73 VCLT. 87 ILC, ‘Draft Articles on the Efects of Armed Conficts on Treaties’ (2011) II(2) Yearbook of International Law Commission 107. 88 Ibid articles 2(b) and 3 ILC Draft Articles on the Efects of Armed Conficts on Treaties. 89 Ibid article 7. 90 Ibid annex. 91 On the concept of jus cogens, see article 53 VCLT; see also Eggett, § 6 and Stoica, § 6.2.D.I., in this textbook. 174 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C Article 42 VCLT suggests that the enumerated termination/suspension grounds are exclusive. However, it is debatable whether by means of customary international law, or as forms of implied consent, desuetude or obsolescence constitute additional grounds. The former refers to a consistent practice of the parties to a treaty that runs counter to their treaty obligations. The latter refers to the expiration of the treaty through disuse. Another debatable termination ground is the full performance of a treaty when the treaty itself does not explicitly provide for such eventuality. Finally, it is only logical that a bilateral treaty comes to an end when one of the two State parties loses its international legal personality, unless of course there is a successor State. II. INVALIDIT Y Under specifc circumstances, treaties may lose their validity, although this occurs very rarely. Invalidity has diferent legal consequences compared to termination. While the latter releases the parties from their treaty obligations from the point of the termination on, invalidity exonerates the injured parties from the legal efects from the point of conclusion of the treaty. Practically, acts having been performed in execution of a void treaty before its invalidation may need to be reversed.92 However, claims of reversal cannot be made by a party that has generated the grounds for the invalidity.93 1. Absolute Grounds for Invalidity The VCLT enumerates three absolute grounds for invalidity, which automatically render the treaty null and void. First, a treaty is void when the consent of a State to be bound by the treaty has been a product of coercion of a representative of a State through acts or threats directed against him or her.94 Second, a treaty is void when the consent is a product of coercion of the State itself by the illegal threat or use of force ‘in violation of the principles of international law embodied in the Charter of the United Nations’ (article 52 VCLT). The last words exclude any legal threat or use of force after an authorisation of the UN Security Council or in self-defence.95 Only military use of force gives rise to invalidity. A treaty cannot be invalidated if a State has been compelled, say, under the pressure of economic sanctions, or the political pressure from a former coloniser.96 Third, a treaty is void if, at the time of its conclusion, it conficted with an existing jus cogens rule.97 2. Relative Grounds for Invalidity The VCLT also lists fve relative grounds for invalidity. They do not immediately nullify the treaty, but rather give a State the right to retrospectively annul its consent to be 92 93 94 95 96 Article 69(2) VCLT. Article 69(3) VCLT. Article 51 VCLT. On the use of force, see Svicevic, § 13, in this textbook. ‘Declaration on the Prohibition of Military, Political and Economic Coercion in the Conclusion of Treaties’ annexed to the ‘Final Act of the Vienna Conference on the Law of Treaties’ UN Doc A/CONF.39/26. 97 Article 53 VCLT. On jus cogens, see also Eggett, § 6 and Stoica, § 6.2.D.I., in this textbook. S O U R C E S O F I N T E R N AT I O N A L L A W 175 bound by that treaty. This would practically mean the nullifcation of a bilateral treaty, or a withdrawal of the victim State from a multilateral treaty with retrospective efect. In the latter scenario, though, the rights and obligations of other treaty parties would remain unafected.98 Contrary to the consequences of absolute grounds, there is the possibility for severing the clauses to which the relative grounds are related, instead for nullifying the whole treaty.99 Relative grounds are the following: (a) A ‘manifest’ violation of ‘fundamental’ internal law provisions regarding competence to conclude treaties (article 46(1) VCLT). The VCLT goes on to clarify that ‘[a] violation is manifest if it would be objectively evident to any State conducting itself in the matter in accordance with normal practice and in good faith’ (article 46(2) VCLT). The term ‘fundamental’ points to constitutional or equivalent rules. (b) Omission by a State representative to observe specific restrictions on authority to express the consent of their State, on the precondition that the other negotiating parties had been duly notified (article 47 VCLT). (c) An error that ‘relates to a fact or situation which was assumed by [the affected] State to exist at the time when the treaty was concluded and formed an essential basis of its consent to be bound by the treaty’ (article 48(1) VCLT). Had the error been foreseeable or caused by the affected State itself, it cannot be invoked as a ground for invalidity. The same is true if the error relates only to the wording of treaty text (articles 48(2) and 48(3) VCLT). (d) Fraudulent conduct of another negotiating State (article 49 VCLT). (e) Corruption of a representative of the affected State, directly or indirectly by another negotiating State (article 50 VCLT).100 E. RESERVATIONS TO TREATIES I. RESERVATIONS Article 2(1)(d) VCLT defnes a reservation as a unilateral statement, however phrased or named, made by a State, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to that State. Reservations are one way in which States express their disagreement with certain provisions and exclude their legal efect. States disagreeing with one or several 98 Article 69(4) VCLT. 99 Article 44(4) VCLT. 100 Article 50 VCLT. 176 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C provisions with may thus nonetheless adopt and ratify the treaty without compromising its entirety. For such reasons, reservations provide a compromise whereby, especially for multilateral treaties, they can achieve widespread adoption and acceptance by numerous States.101 While reservations are a useful tool for States in excluding or modifying a treaty’s legal efects, there are certain cases where reservations are prohibited. This concerns three situations: • • • If the reservation is incompatible with the object and purpose of a treaty; If the reservation is prohibited by the treaty; or If the treaty provides only for specifed reservations and the reservation in question falls beyond the scope of such specifed reservation.102 These limitations are for the most part reasonable. For example, reservations which are incompatible with the object and purpose of a treaty could render the very logic behind the treaty void. Where a treaty expressly provides for reservations, there is no need for other States party to the treaty to accept the reservation made by one of the State parties.103 In some cases, however, State parties to a treaty may need to accept reservations. If, for example, there is a limited number of negotiating States and the object and purpose of the treaty requires its application to all the parties as an essential condition of their consent, then reservations made to such treaty need to be accepted by all parties.104 Another scenario where reservations need to be accepted is where the treaty in question is a constituent instrument of an international organisation, in which case a competent organ of that organisation needs to accept the reservation.105 Reservations and objections to reservations may be withdrawn at any time and do not require the consent of any State which had previously accepted such reservation.106 Some treaties explicitly prohibit reservations. For example, article 25 of the Kyoto Protocol provides that ‘[n]o reservations may be made to this Protocol’.107 Another example is article 120 of the Rome Statute of the International Criminal Court.108 101 102 103 104 105 106 107 Kaczorowska (n 43) 98. Cf. article 19 VCLT. Article 20(1) VCLT. Article 20(2) VCLT. Article 20(3) VCLT. Article 22 VCLT. Kyoto Protocol to the United Nations Framework Convention on Climate Change (adopted 11 December 1997, entered into force 16 February 2005) 2303 UNTS 162. 108 Rome Statute of the International Criminal Court (adopted 17 July 1998, entered into force 1 July 2002) 2187 UNTS 3. S O U R C E S O F I N T E R N AT I O N A L L A W 177 II. INTERPRETATIVE DECLARATIONS Another unilateral statement which a State can make when joining a treaty is an interpretative declaration. Interpretative declarations are statements in which a State indicates or clarifes what it understands to be the scope or nature of specifc treaty provisions. Interpretative declarations do not modify the provisions of a treaty but may later be followed by other States in how they too interpret certain provisions of that treaty. Beyond the standard interpretative declaration, a State may also make a conditional interpretative declaration. Such a declaration signals that a State does not wish to be bound by certain provisions unless a specifc interpretation is accorded to those provisions. Conditional interpretative declarations are therefore subject to the same rules as reservations.109 The distinction between reservations, interpretative declarations, and conditional interpretative declarations in practice is often not clear-cut. States sometimes use ambiguous language when entering these unilateral statements, ultimately making it difcult to determine their intention. F. INTERPRETATION OF TREATIES I. INTERPRETATIVE AUTHORITIES As with many other areas of treaty law, the interpretation of treaties is no simple task. As a body of provisions usually drafted and negotiated over long periods of time, and which apply to numerous States with binding legal efect, the interpretation of treaties is one of the most crucial aspects concerning the law of treaties. One of the starting points in discussing treaty interpretation is precisely who has the authority to interpret treaties. Given that treaties are legal texts distinct from the domestic laws of States, it is necessary to understand both who may interpret them and precisely how they are to be interpreted. In principle, every application of a treaty implies interpretation; it would not be possible to apply the provisions of a treaty without frst reading and interpreting its provisions.110 On this basis, all entities concerned with the treaty in question engage in its interpretation. Actors who have the competence to interpret treaties and their provisions besides States include international organisations, international courts, and domestic courts. 109 ILC, ‘Guide to Practice on Reservations to Treaties’ (2911) II(2) Yearbook of the International Law Commission 26. 110 Oliver Dörr, ‘Chapter 31’ in Oliver Dörr and Kirsten Schmalenbach (eds), Vienna Convention on the Law of Treaties: A Commentary (2nd edn, Springer 2018) 567–568. 178 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C II. GENERAL RULE OF INTERPRETATION Article 31 VCLT provides the general rule of interpretation of treaties. It refects customary international law and embodies a multifaceted approach to interpreting treaties.111 Treaties are frst and foremost to be interpreted in good faith, and the ordinary meaning of terms are to be used in context and in light of a treaty’s object and purpose.112 The interpretation of a treaty includes its context, which in addition to the main text, preamble, and annexes also includes other agreements which relate to the treaty made between the parties in connection with the treaty, or an instrument made between one or more parties in connection with the treaty accepted by other parties as an instrument to the treaty. In addition, context includes subsequent agreements and practice of State parties regarding the interpretation of a treaty. This may clarify how they interpret it and even indicate that they consider such an interpretation efective for purposes of applying its provisions. It also makes perfect sense that given the wording of article 31(1), special meaning is given to terms only if the parties so intended. In practice, most treaties usually start with a section defning terms used with the treaty, in this way clarifying how such terms are not only understood in the context of the treaty, but how they are applied throughout its provisions. One of the reasons behind the interpretation of treaties suggested by article 31 is that, naturally by examining the very text and context of a treaty, it is presumed that a treaty constitutes an authentic expression of the intentions of its parties.113 Only by examining the treaty itself can one ascertain the intention of its drafters. III. SUPPLEMENTARY MEANS OF INTERPRETATION Beyond the general rule of interpretation, article 32 VCLT provides supplementary means of interpretation. Certain elements may thus be used in furthering the precise meaning of provisions if the application of the general rules prove unsatisfactory (to the extent that ambiguities remain or the application of article 31 leads to manifest absurdity or unreasonableness). They thus carry less weight because they are in efect meant to complement and clarify the application of article 31.114 Supplementary means of interpretation under article 32 most commonly include the preparatory work of a treaty, including documents related to negotiation history between the State parties and drafting history of the treaty. Preparatory works are usually available to the negotiating parties, thereby excluding unilateral sources and 111 Chang-Fa Lo, Treaty Interpretation under the Vienna Convention of the Law of Treaties: A New Round of Codifcation (Springer 2017) 39–44. 112 Article 31(1) VCLT. 113 Dörr (n 84) 620–624. 114 Oliver Dörr, ‘Article 32’ in Oliver Dörr and Kirsten Schmalenbach (eds), The Vienna Convention on the Law of Treaties: A Commentary (2nd edn, Springer 2018) 618. S O U R C E S O F I N T E R N AT I O N A L L A W 179 confdential sources, that may not necessarily have been introduced or made available to other negotiating States parties.115 IV. OTHER METHODS OF TREAT Y INTERPRETATION In addition to those rules of interpretation mentioned above, there exist a number of methods of treaty interpretation.116 • Teleological interpretation: requires that the meaning of words and terms be interpreted in light of the object and purpose of a treaty. In such cases, a teleological interpretation aims to give efect to the overall aims and objectives of a treaty. • Systematic interpretation: requires a treaty to be interpreted with the ordinary meaning of words and that all parts of a treaty as well as corresponding documents produced between the parties be taken into account. Such documents would include the negotiation and drafting history of a treaty. • Textual interpretation: requires that the ordinary meaning of words be used to interpret treaties, that such meaning be clear, and that upon interpretation does not lead to unreasonable or absurd outcomes. It is worth mentioning that other methods of interpretation may difer from those found in the VCLT. There is no concrete position as to which method one should adopt when interpreting treaties. Some authors take the VCLT as a point of departure, whereas others consider either the complementary or exclusive position of other methods of interpretation. G. CONCLUSION Treaty law remains one of the most fundamental felds within international law, interwoven with almost every other branch of international law. At its core, treaty law, most notably as represented within the VCLT, governs the application rules to international treaties. Although treaties remain the most conclusive evidence of international cooperation, they are not without controversy. The very nature of treaties, their negotiation and drafting, invalidation and termination, continue to give rise to various debates in international law. Equally so, the very interpretation of treaties in international law remains a delicate art. The law of treaties has also been a changing feld. While in the past it was a transaction of rights and duties between States, today organisations and actors without legal capacity may too engage with treaty law (be it in negotiation, drafting, or conclusion). Finally, it is worth keeping in mind that treaty law’s approach in time means it has oftentimes contributed to problems in the past. Treaty-making before the advent of human rights serves as just one example of this, where treaty law enabled the subdivision and claiming of land and the arbitrary separation of peoples across these lands. 115 Ibid 620–624. 116 See also Kaczorowska (n 43) 124–126. 180 TA X I A R C H I S F I S K AT O R I S A N D M A R K O S V I C E V I C BOX 6.1.4 Further Readings Further Readings · O Dörr and K Schmalenbach (eds), Vienna Convention on the Law of Treaties: A Commentary (2nd edn, Springer 2018) · R Gardiner, Treaty Interpretation (2nd edn, OUP 2017) · DB Hollis (ed), The Oxford Guide to Treaties (2nd edn, OUP 2017) · R Kolb, The Law of Treaties: An Introduction (Edward Elgar 2016) · B Mulamba Mbuyi, Droits des Traités Internationaux: Notes de Cours à l’Usage des étudiants en Droit (L’Harmattan 2009) §§§ S O U R C E S O F I N T E R N AT I O N A L L A W 181 § 6.2 CUSTOMARY INTERNATIONAL LAW VICTOR STOICA BOX 6.2.1 Required Knowledge and Learning Objectives Required knowledge: History of International Law; Nature and Purpose of International Law; Consent Learning objectives: Understanding what customary international law as a source of international law is, and who directly and indirectly contributes towards its formation and identification. A. INTRODUCTION Customary international law is unwritten; it is tacit agreement. Prior to World War II, it represented the main mechanism through which international law was created. It has been argued that the current framework of customary international law is, to a certain degree, the result of a rather regionalised State practice.117 This practice became ‘general’ by colonial domination and European resistance towards eforts of newly independent States in the 1950s and 1960s to participate in the custom-making and codifcation process on their own terms.118 Today, customary international law is no longer the primary, but remains one of the most important, sources along with treaties. In times of crisis of classic treaty-making, it is arguably even of renewed relevance, by ofering binding rules irrespective of hyperpolitical treaty negotiations. Article 38(1) of the Statute of the International Court of Justice (ICJ)119 is essential for understanding the meaning and content of customary international law, which rests on the implied consent of States.120 There is much controversy around the concept, which is closely connected to the unwritten nature of customary law and the way it comes into being. Because of its Statecentredness, the legitimacy of customary international law may seem debatable.121 One of the main reasons for this rather convoluted understanding is that, as opposed to treaties, the formation of customary international law does not follow a predictable path or an 117 Patrick Kelly, ‘Customary International Law in Historical Context’ in Brian Lepard (ed), Reexamining Customary International Law (CUP 2017) 47. 118 On the history of international law, see González Hauck, § 1, in this textbook. 119 Statute of the International Court of Justice (adopted 17 December 1963, entered into force 31 August 1965) 993 UNTS 33. 120 Vincy Fon and Francesco Parisi, ‘Stability and Change in International Customary Law’ (2009) 17 Supreme Court Economic Review 279. On consent, see González Hauck, § 2.2, in this textbook. 121 John Tasioulas, ‘Opinio Iuris and the Genesis of Custom: A Solution to the “Paradox”’ (2007) 26 Aust YBIL 199. 182 VICTOR STOICA exact and regulated procedure. It may seem that customary international law blooms slowly and appears abruptly. While the traditional view is that the creation of custom essentially entails a substantial amount of time to pass for its creation, recent doctrine has also acknowledged the possibility for the creation of an ‘instant custom’,122 in certain emerging domains such as space law. The United Nations General Assembly, through is Resolutions, is also regarded as a main contributor to the creation of instant customs.123 Over the last years, eforts to codify customary international law and systematise its identifcation have certainly contributed to its understanding. Worth mentioning are the International Law Commission’s (ILC) Draft conclusions on Identifcation of Customary International Law124 and the ILA Statement of Principles Applicable to the Formation of General Customary International Law.125 The same is true for the jurisprudence of the ICJ. The aim of this chapter is to give an overview of how customary law as one of the sources of international law is formed and identifed. By doing so, it will also touch upon some of the contemporary controversies revolving around customary international law. B. CONSTITUTIVE ELEMENTS OF CUSTOMARY LAW I. GENERAL PRACTICE 1. Actions and Active Doing The frst element required to form custom is general practice. What is primarily relevant is State practice.126 States are abstract entities, with no material form through which they could manifest their activities. High ofcials, such as Heads of State or Ministers, municipal courts or legislative bodies may be viewed as the limbs through which States act and develop practice. However, not all actions performed by States may create custom. One classic example for the formation of customary international law is maritime law, which was ‘almost entirely customary international law’.127 Not only physical acts (such 122 Michael Sharf, ‘Seizing the Grotian Moment: Accelerated Formation of Customary International Law in Times of Fundamental Change’ (2010) 43 Cornell International Law Journal 440, 445–446. 123 Ibid. 124 ILC, ‘Draft Conclusions on Identifcation of Customary International Law, with Commentaries’ (70th session, 30 April–1 June and 2 July–10 August 2018) UN Doc A/73/10 122–156. 125 Committee on Formation of Customary (General) International Law, ‘Final Report of the Committee. Statement of Principles Applicable to the Formation of General Customary International Law’ in International Law Association Report of the Sixty-Ninth Conference (London 2000). 126 Draft Conclusion 4 (n 8) 130. See also Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v USA) (Merits) [1986] ICJ Rep 14 [184]. 127 Richard Barns and others, ‘The Law of the Sea: Progress and Prospects’ in David Freestone and others (eds), The Law of the Sea. Progress and Prospects (OUP 2006) 22; see also North Sea Continental Shelf (Federal Republic of S O U R C E S O F I N T E R N AT I O N A L L A W 183 as the exercise of fshing rights or the seizure of foreign vessels) may constitute practice, but also legal acts.128 Illustratively, if States enact legislation to protect fsh within 200 miles of their coasts, there is potential for the creation of a rule of customary international law.129 The distinctions between State practice and opinio juris are not always clear-cut, leading to difcult questions in practice. Yet, this should not be regarded as negative, especially since the way States act continues to diversify.130 2. Inaction and Not-Doing (Acquiescence) Sometimes, omissions may also represent State practice, for the silence of States can be interpreted as approval.131 A State’s inaction, thus, sometimes has legal efects. Unsurprisingly, this has given rise to controversy. The ICJ has greatly contributed to clarifying the circumstances under which this is the case. In the Temple of Preah Vihear case, the Court made clear that inaction may only be read as approval or acquiescence if ‘the circumstances called for some reaction, within a reasonable period’.132 The ICJ confrmed its fndings in other judgments and held that ‘silence may also speak, but only if the conduct of the other State calls for a response’.133 The ILC provides further examples of omissions that may lead to the creation of custom: ‘abstaining from instituting criminal proceedings against foreign State ofcials; refraining from exercising protection in favour of certain naturalized persons; and abstaining from the use of force’.134 Doctrine confrms that only the omissions which are clear in their scope may constitute relevant practice.135 Omissions must, thus, be carefully interpreted in order to determine the true intention of the State that did not perform a particular action. 3. Statements Regarding the value of public statements of States, diferent opinions exist. Some argue that they should rather be considered under the subjective element, opinio juris.136 128 129 130 131 132 133 134 135 136 Germany v Denmark; Federal Republic of Germany v the Netherlands) (Judgment) [1969] ICJ Rep 3. On the law of the sea, see Dela Cruz and Paige, § 15, in this textbook. Laurence Boisson de Chazournes, ‘Qu’est-ce que la Pratique en Droit International?’ in Société française pour le droit international, La pratique et le droit international: Colloque de Genève (Pedone 2004). Ibid. María Vásquez Callo-Müller and Iryna Bogdanova, ‘What Is the Role of Unilateral Cyber Sanctions in the Context of the Global Cybersecurity Law-Making?’ (Völkerrechtsblog, 10 May 2022) <https:// voelkerrechtsblog.org/what-is-the-role-of-unilateral-cyber-sanctions-in-the-context-of-the-globalcybersecurity-law-making/> accessed 10 August 2023. Draft Conclusion 6 (n 124) 133. Case concerning the Temple of Preah Vihear (Cambodia v Thailand) (Merits) [1962] ICJ Rep 6. Sovereignty over Pedra Branca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia v Singapore) (Judgment) [2008] ICJ Rep 12 [121]. Draft Conclusions (n 124) 133. Maurice H Mendelson, ‘The Formation of Customary International Law’ (1998) 272 RdC 155, 207. Anthony D’Amato, The Concept of Custom in International law (Cornell UP 1971) 49; Anthea Roberts, ‘Traditional and Modern Approaches to Customary International Law: A Reconciliation’ (2001) 95 AJIL 757. 184 VICTOR STOICA According to a more progressive view, statements (especially those of high ofcials) may constitute State practice. In support of this, certain scholars point out that some ‘important acts of state behaviour, such as recognition of another state, do not need a physical act’.137 It has been argued that what matters is that statements may constitute either State practice or opinio juris depending on the relevant contextual circumstances.138 For example, a statement of a head of State or a foreign minister, which are the actors representing the State on the international plane, may constitute practice.139 4. What Does ‘General’ Mean? A crucial question that arises is how widespread a practice must be. A universalist perspective would mean that ‘all or almost all of the nations of the world engage in it’.140 Even if this view has certain merit, it is nearly impossible to determine if more than 190 States have engaged in a certain practice.141 Further, practice is rarely virtually homogenous.142 The ILC opted for a pragmatic but abstract solution, stating that for practice to be general, it must be ‘sufciently widespread and representative as well as consistent’.143 This three-pronged standard is lower; it does not require unanimity or even majority. a) Sufficiently Widespread Widespread practice is generally understood as ‘existing or happening in many places and/or among many people’.144 The ICJ has not defned the concept, nor did the ILC, which quotes the North Sea Continental Shelf cases, in which the ICJ concluded that the practice in question must be ‘both extensive and virtually uniform’,145 or ‘settled practice’.146 These standards are not universal, nor were they relevant in all cases in which the application of customary international law was at stake. The only clarifcation provided is that practice is sufciently widespread when it is not ‘contradictory or 137 Jorg Kammerhofer, ‘Uncertainty in the Formal Sources of International Law: Customary International Law and Some of Its Problems’ (2004) 15 EJIL 526. 138 Mendelson (n 135) 206. 139 Ibid. 140 Jack Landman Goldsmith, ‘A Theory of International Law’ (1999) University of Chicago Law School, John M Olin Law & Economics Working Paper No. 63, 7 <https://papers.ssrn.com/sol3/papers.cfm?abstract_ id=145972> accessed 16 August 2023. 141 Ibid. 142 Niels Petersen, ‘The International Court of Justice and the Judicial Politics of Identifying Customary International Law’ (2017) 28 EJIL 377. 143 Draft Conclusion 8 (n 124) 135. 144 ‘Widespread’, Cambridge Advanced Learner’s Dictionary & Thesaurus (CUP) <https://dictionary.cambridge.org/ dictionary/english/widespread> accessed 17 August 2023. 145 North Sea Continental Shelf (n 27) [74]. 146 Ibid [77]. S O U R C E S O F I N T E R N AT I O N A L L A W 185 inconsistent’.147 It would then seem that the frst criterion is defned through what it is not. In other words, practice may be widespread if it is not limited. b) Sufficiently Representative Representative practice is generally understood as ‘typical of, or the same as, others in a larger group of people or things’.148 At frst glance, it might seem that the concept of ‘representative’ has common features with the concept of ‘widespread’, especially because the number of entities participating in the creation of custom is relevant in both cases. However, in comparison, representative practice is rather qualitative, whereas widespread practice is quantitative. The ICJ has not addressed what ‘representative’ means. According to the ILC, it must take into consideration the ‘various interests at stake and/or the various geographical regions’.149 Therefore, for practice to be representative, the approach of certain States has more weight than others. c) Consistency Consistency is generally understood as ‘the quality of always behaving or performing in a similar way, or of always happening in a similar way’.150 This standard implies that practice should manifest stability over time.151 As such, if the behaviour of States fuctuates over time, it would be difcult to identify a general practice.152 The question, here, is whether there is a need for uniformity of practice (complete consistency) for the formation of custom or whether a lower standard sufces. In the Nicaragua case, the ICJ found that complete consistency is not required and that the corresponding practice may not be in ‘absolute conformity with the rule’.153 The ‘virtual uniformity’ concept used in the North Sea Continental Shelf is also relevant here, even if the period of time in which it is developed is short.154 II. ACCEPTED AS LAW (OPINIO JURIS ) For general practice to become custom, it needs, furthermore, to be performed out of a sense of a legal obligation. The ICJ confrmed that States must feel that they are respecting 147 Ibid. 148 ‘Representative’, Cambridge Advanced Learner’s Dictionary & Thesaurus (CUP) <https://dictionary.cambridge. org/dictionary/english/representative> accessed 17 August 2023. 149 Draft Conclusion 8 (n 124) 135. 150 ‘Consistency’, Cambridge Advanced Learner’s Dictionary & Thesaurus (CUP) <https://dictionary.cambridge.org/ dictionary/english/consistency> accessed 17 August 2023. 151 Fon and Parisi (n 120) 283. 152 Ibid. 153 Military and Paramilitary Activities in and Against Nicaragua (n 126) [186]. 154 North Sea Continental Shelf (n 127) [74]. 186 VICTOR STOICA a legal obligation.155 This criterion is the subjective element of customary international law, opinio juris. How does one determine what an abstract entity such as a State believes? Unsurprisingly, this element of custom is controversial. The ILC sheds some light on the tools that may evidence opinio juris, such as ‘public statements made on behalf of states; ofcial publications; diplomatic correspondence; decisions of national courts; treaty provisions; and conduct in connection with resolutions adopted by an international organisation or intergovernmental conference’.156 The distinction between acts (such as the ones enumerated above) that confrm the perception of States to be bound by legal obligations and those evidencing actions out of courtesy is also not clear. The ICJ, in the North Sea Continental Shelf cases, confrmed that ‘there are many international acts, e.g. in the feld of ceremonial and protocol, which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty’.157 As such, ‘it is difcult to determine what states believe as opposed to what they say’.158 These uncertainties regarding a precise way opinio juris should be determined have led certain authors to conclude that the subjective element should be less relevant,159 and that practice should be at the forefront of identifying customary international law. Nevertheless, it is rather generally accepted that ‘while opinio juris confers the legal bindingness of custom, practice, it is argued, can be understood as what provides custom with normative content’.160 In other words, while practice provides what the norm contains, opinio juris is what confers to that norm its binding character. Opinio juris is, thus, essential for the creation of customary international law. C. WHO IS BOUND BY CUSTOM? I. THE PERSISTENT OBJECTOR The ‘persistent objector’ doctrine captures situations in which a State expressly objects to a rule of customary international law when that rule is in the process of formation. It provides that, in these cases, said rule will not be applicable to that State. 155 156 157 158 159 Ibid. Draft Conclusion 6 (n 8) 133. North Sea Continental Shelf (n 18) [77]. Roberts (n 136) 757. Pierro Mattei-Gentili, ‘The Quest for Opinio Juris: An Analysis of Customary Law, from Hart’s Social Rules to Expectations and Everything in the Middle’ (2020) 34 Noesis 89. 160 Maiko Meguro, ‘Distinguishing the Legal Bindingness and Normative Content of Customary International Law’ (2017) 6(11) ESIL Refection <https://esil-sedi.eu/post_name-1149/> accessed 16 August 2023. S O U R C E S O F I N T E R N AT I O N A L L A W 187 The timing of contestation is relevant, because potential objections of States which are performed after customary international law was formed are no longer relevant. In other words, States that did not object during the formation of custom must comply with the created rules. The role of the consistent objector doctrine is to respect States’ sovereignty and protect them from the imposition of rules against their will; yet, if the support for the new rule is sufciently widespread, ‘the convoy of the law’s progressive development can move forward without having to wait for the slowest vessel’.161 II. SPECIALLY AFFECTED STATES The ‘specially afected States’ doctrine aims to take into account the fact that some States were ‘particularly involved in the relevant activity or most likely to be concerned with the alleged rule’.162 For example, the rise of the level of seas and oceans imply signifcant threats to small island States for multiple reasons, such as the concentration of people and infrastructure present in coastal areas.163 These States may be considered as specially afected for the creation and identifcation of customary international law related to sea level rise. This is not to argue that the specially afected States are the only ones that contribute to the creation of customary international law in a particular feld. Rather, their practice should carry more weight than the practice of States that are not in the same position. D. SPECIAL CUSTOMARY INTERNATIONAL LAW I. JUS COGENS NORMS Jus cogens norms, or the peremptory norms of public international law, are rules ‘accepted and recognized by the international community as a whole . . . from which no derogation is permitted’.164 They thus reside at the top of the hierarchy of norms. While the legal justifcation of jus cogens is not entirely clear, one explanation is that they are created through custom. In other words, some customary norms ‘are considered so vital that they cannot be contracted out of by individual states’.165 161 International Law Association (n 125) 28. 162 Draft Conclusions (n 124). 163 Rosanne Martyr-Koller and others, ‘Loss and Damage Implications of Sea-Level Rise on Small Island Developing States’ (2021) 50 COSUST 245. 164 Article 53 VCLT. On jus cogens, see Eggett, § 6, in this textbook. 165 Roozbeh Baker, ‘Customary International Law in the 21st Century: Old Challenges and New Debates’ (2010) 21 EJIL 177. 188 VICTOR STOICA II. REGIONAL CUSTOMARY INTERNATIONAL LAW At the opposite end of the spectrum rests regional (or particular) customary international law. By way of example, the Arbitral Tribunal in the Eritrea/Yemen Arbitration recognised the possibility of a custom to exist on a regional or even a bilateral basis,166 practice which may be based upon a need for ‘respect for regional legal traditions’.167 In the Asylum case, the ICJ accepted the possibility of regional customs to exist, even if in the case at hand it concluded that the Colombian government did not prove the existence of such a rule.168 In a later case, the Court emphasised the relevance of practice between two States.169 Subsequent practice can also be taken into account when determining the content of customary norms. In its Nicaragua judgment, the Court appeared to agree that regional customary international law, ‘particular to the inter-American legal system’,170 exists. E. CONCLUSION Beyond the general assertion that custom exists of two elements, State practice and accompanying opinio juris, there are no clear, universally applicable, and fxed rules for the creation of customary international law. However, the lack of such parameters is not in itself a disadvantage, given the ever-evolving nature of international law. Customary international law is characterised by agility and has the potential to address multiple legal frameworks: it may be regional or global, it may be confrmed through treaties or detached from them, and it may be general or special. Consequently, fexibility in the identifcation of customary law may appear suitable, as it refects the ever-changing developments of international law and policy. The role of the ICJ in identifying customary law is essential: Customary law, being vague and containing gaps compared with written law, requires precision and completion about its content. This task, in its nature being interpretative, would be incumbent upon the Court. The method of logical and teleological interpretation can be applied in the case of customary law as in the case of written law.171 Even though custom does not anymore occupy the place it historically has, it remains important. It is a fragile source and should be carefully addressed by international courts and tribunals, policy makers, and all actors playing on the scene of international relations. 166 Government of the State of Eritrea and Government of the Republic of Yemen (Phase Two: Maritime Delimitation) (2002) 119 ILR 417, 448. 167 Draft Conclusion 16 (n 124) 154. 168 Colombian-Peruvian asylum case (Colombia v Peru) (Judgment) [1950] ICJ Rep 266 [277]. 169 Case concerning Right of Passage over Indian Territory (Portugal v India) (Merits) [1960] ICJ Rep 6 [44]. 170 Military and Paramilitary Activities in and against Nicaragua (n 26) [199]. 171 North Sea Continental Shelf (Federal Republic of Germany v Denmark; Federal Republic of Germany v the Netherlands) (Dissenting Opinion of Judge Tanaka) [1969] ICJ Rep 172. 189 S O U R C E S O F I N T E R N AT I O N A L L A W BOX 6.2.2 Further Readings Further Readings · J Crawford, Chance, Order, Change: The Course of International Law, General Course on Public International Law (Brill 2014) · J D’Aspremont, International Law as a Belief System (CUP 2017) · A Roberts, Is International Law International? (OUP 2017) · H Lauterpacht, The Function of Law in the International Community (OUP 2011) §§§ 190 CRAIG EGGETT § 6.3 GENERAL PRINCIPLES CRAIG EGGETT BOX 6.3.1 Required Knowledge and Learning Objectives Required knowledge: Sources of International Law; Subjects and Actors; Positivism; Consent Learning objectives: Understanding the background to article 38(1)(c) ICJ Statute and how general principles can be identified; understanding what general principles (can) do in international law. A. INTRODUCTION Article 38(1) of the Statute of the International Court of Justice’s (ICJ) list of generally accepted sources of international law concludes with sub-paragraph (c)’s ‘general principles of law recognised by civilised nations’.172 That the fnal three words of this provision are to be discarded is clear, yet doing so is just the beginning of thorough engagement with general principles in international law.173 This source of law has received considerably less attention than treaties and customary law, and there are few unequivocally recognised examples of general principles. Article 38(1)(c) has never been explicitly relied on by the ICJ as a basis of a decision. The discourse on general principles received a signifcant boost when, in 2017, the International Law Commission (ILC) decided to include the topic on its programme.174 This chapter aims to provide an overview of the core aspects of the ongoing discussion on general principles in international law. It is structured around three main questions: (1) What kind of norms are general principles? (2) How are they ascertained? and (3) What functions do they perform? These questions overlap to an extent, yet they provide a basic logical structure to examine general principles and their place in the international legal system. 172 Statute of the International Court of Justice (adopted 17 December 1963, entered into force 31 August 1965) 993 UNTS 33. 173 For a discussion of the broader issue of reference to ‘civilisation’ in this provision, and in international law more generally, see Sué González Hauck, ‘All Nations Must Be Considered to Be Civilized: General Principles of Law between Cosmetic Adjustments and Decolonization’ (Verfassungsblog, 21 July 2020) <https:// verfassungsblog.de/all-nations-must-be-considered-to-be-civilized/> accessed 9 August 2023; Ntina Tzouvala, Capitalism as Civilisation (CUP 2020) chapter 1. 174 The overview of the ILC’s work on general principles can be found here: ILC, ‘Analytical Guide to the Work of the International Law Commission’ <https://legal.un.org/ilc/guide/1_15.shtml> accessed 9 August 2023. S O U R C E S O F I N T E R N AT I O N A L L A W 191 B. THE NATURE OF GENERAL PRINCIPLES I. HISTORY AND ORIGINS OF GENERAL PRINCIPLES IN INTERNATIONAL LAW Both the wording and history of the ICJ Statute confrm that general principles have a role as applicable law in the settlement of disputes. The drafting of article 38 ICJ Statute is based on the corresponding provision of the PCIJ Statute, which contains identical wording, yet the history extends further back than the drafting of the PCIJ Statute.175 For example, references to ‘principles’ as a source of applicable law were included in the Arbitral Procedure Regulations 1875,176 the First Hague Convention establishing the PCA,177 and the Convention Relative to the Creation of an International Prize Court 1907.178 While difering in their precise construction, the references to ‘principles’ illustrates that early practice recognised a role for a source of international law beyond treaties and custom. Even early arbitral practice suggested a role for general principles in international law. Examples are the Walfsh Bay Boundary case179 or the Pious Fund case,180 in which the Tribunal found that the principle of res judicata (Latin: ‘a matter judged’), which has its origins in domestic systems and Roman law, was applicable in international law and so governed the decision in question.181 The original draft of article 38 referred to ‘the rules of international law as recognised by the legal conscience of civilized nations’.182 This formulation represents a departure from some earlier references to ‘principles of justice and equity’. The members of the Advisory Committee debated the role that this third source of law would play and the powers that it would grant to the Court.183 Throughout the discussions of the Advisory Committee, there was broad agreement 175 For an overview, see Imogen Saunders, General Principles as a Source of International Law: Article 38(1)(c) of the Statute of the International Court of Justice (Hart 2021) 21–38. 176 Institute de Droit International, Projet de règlement pour la procédure arbitrale internationale [1875] Vol 1, article 22 (referring to ‘principles of law which are applicable by virtue of the rules of international law). 177 Convention (I) on Pacifc Settlement of International Disputes (adopted 29 July 1899, entered into force 4 September 1900) 187 CTS 410, article 48. 178 Convention Relative to the Creation of an International Prize Court 1907 (signed 18 October 1907) 205 CTS 381, article 7 (referring to ‘general principles of justice and equity’). 179 Walfsh Bay Boundary Case (Germany v Great Britain) [1911] 11 RIAA 263. 180 The Pious Fund Case (United States of America v Mexico) [1902] 9 RIAA 1. 181 Ibid 7–10. 182 Permanent Court of International Justice: Advisory Committee of Jurists, Procès-verbaux of the Proceedings of the Committee (Van Langenhuysen Brothers 1920) 13th Meeting, 306. 183 See the Procès-verbaux of the 13th, 14th, and 15th meetings. For an overview, see, for example, Saunders (n 175) 38–46; Ole Spiermann, ‘The History of Article 38 of the Statute of the International Court of Justice: “A Purely Platonic Discussion?”’ in Samantha Besson and Jean d’Aspremont (eds), The Oxford Handbook on the Sources of International Law (OUP 2017) 170–173. 192 CRAIG EGGETT that the purpose of this provision was to make available to the Court a source of applicable law that could be relied upon in the absence of any applicable treaty or customary rules. The legal nature of general principles as a source of applicable law was apparent from the outset. II. GENERAL PRINCIPLES, RULES, AND OTHER NORMS A central issue is whether general principles, in and of themselves, can be a source of obligations in international law. The decision to use the term ‘principle’ in place of the original ‘rule’ could suggest that general principles are a different kind of norm, distinct from concrete rules of law. Indeed, there are authors who argue that general principles are broader and vaguer norms that do not impose direct obligations but provide a more general framework for the interpretation and application of rules and discretion to judges.184 In a similar vein, some would argue that general principles have natural law overtones185 and links to broader values or moral considerations.186 Conversely, some authors would argue that general principles, like the other sources of law, are capable of granting rights and imposing obligations.187 There are others, still, that view general principles as some sort of in-between; as a type of transitory norm between values and concrete rules188 or as a form of ‘inchoate custom’.189 Despite these contrasting positions, it seems clear that international courts and tribunals view themselves as being capable of recognising rights and obligations beyond treaties and customary law. A prominent example of this is the development of many procedural rules of international law, which courts and tribunals have frequently recognised as general principles owing to their presence in domestic law and foundation in certain established ‘legal maxims’.190 184 See, for example, Ulf Linderfalk, ‘General Principles as Principles of International Legal Pragmatics: The Relevance of Good Faith for the Application of Treaty Law’ in Mads Andenas and others (eds), General Principles and the Coherence of International Law (Brill/Nijhof 2019). 185 Igno Venzke, How Interpretation Makes International Law: On Semantic Change and Normative Twists (OUP 2012) 25 (claiming that the approach of the ICJ to general principles has clear natural law overtones). 186 See, for example, South West Africa Cases (Ethiopia v South Africa; Liberia v South Africa) (Second Phase) (Judgment) [1966] ICJ Rep 6, Reply of Ethiopia and Liberia [271] 187 Beatrice Bonafé and Paolo Palchetti, ‘Relying on General Principles in International Law’ in Catherine Brölmann and Yannick Radi (eds), Research Handbook on the Theory and Practice of International Lawmaking (Edward Elgar 2016) 165–168; Alain Pellet, ‘Article 38’ in Andreas Zimmermann and Christian Tams (eds), The Statute of the International Court of Justice: A Commentary (2nd edn, OUP 2012) 251; Craig Eggett, General Principles as Systemic Elements of International Law (PhD Thesis, Maastricht University 2021) chapter III. 188 Roman Kwiecień, ‘General Principles of Law: The Gentle Guardians of Systemic Integration of International Law’ (2017) 37 PolishYIL 235, 242. 189 Olufemi Elias and Chin Lim, ‘General Principles of Law, Soft Law and the Identifcation of International Law’ (1997) 28 NYIL 3, 35. 190 For an overview, see Mathias Forteau, ‘General Principles of International Procedural Law’ (The Max Planck Encyclopedia of International Procedural Law, January 2018) <https://opil.ouplaw.com/display/10.1093/lawmpeipro/e3544.013.3544/law-mpeipro-e3544> accessed 9 August 2023. S O U R C E S O F I N T E R N AT I O N A L L A W 193 BOX 6.3.2 Advanced: Rules and Principles in International Law International lawyers will frequently debate whether something is part of international law; that is, whether it is a legal norm that regulates a given situation or dispute. In doing so, they deploy a range of terms to help delineate the different kinds of norms at play. ‘Rules’ and ‘principle’ are two of the most common such terms. While these terms may mean slightly different things to different people, and indeed the Court saw no relevance to the terminology at all in Gulf of Maine,191 these terms can be used to draw a distinction between concrete norms that impose rights and obligations (rules) and those that underlie the system and infuence the interpretation of rules (principles). If such a distinction is accepted, it may be more accurate to describe general principles in the sense of article 38(1)(c) as a category of rules of international law.192 191 Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v United States of America) (Judgment of a Chamber) [1984] ICJ Rep 246 [79]. It can be a challenge to demarcate general principles from other categories of norms. 192 On this view, see Craig Eggett, ‘The Role of Principles and General Principles in the “Constitutional First, the diferentiation with custom can be particularly difcult to identify.193 Processes” of International Law’ (2019) 66(2) NILR 197; Eggett (n 187) chapter III. Both are unwritten sources of (typically) general application. Further, it seems perfectly possible that there could exist customary rules and general principles that have similar or identical content, as has been recognised in the case of treaty and customary rules.194 Yet, there are key diferences in both the ascertainment and functions of custom and general principles. While custom is anchored in the practice and views of States, the formation of general principles involves a more pronounced role for courts and tribunals in the examination of domestic systems and notions of legal logic. As for jus cogens, the ILC expressed support for the idea that general principles of law could attain jus cogens status.195 However, it should be noted that the label jus cogens denotes a certain elevated status that can be assigned to a norm, regardless of its source, and not a source of law in and of itself. 191 Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v United States of America) (Judgment of a Chamber) [1984] ICJ Rep 246 [79]. 192 On this view, see Craig Eggett, ‘The Role of Principles and General Principles in the “Constitutional Processes” of International Law’ (2019) 66(2) NILR 197; Eggett (n 187) chapter III. 193 On custom, see Stoica, § 6.2, in this textbook. 194 Military and Paramilitary Activities In and Against Nicaragua (Nicaragua v United States of America) (Merits) [1986] ICJ Rep 14 [178]. See also ILC, ‘Text of the draft conclusions provisionally adopted by the Drafting Committee on frst reading’ 74th Session (24 April–2 June and 3 July–4 August 2023) UN Doc A/ CN.4/L.982, draft conclusion 11. 195 ILC, ‘Second Report on Peremptory Norms of General International Law (jus cogens) by Dire Tladi, Special Rapporteur’, 69th Session (1 May–2 June and 3 July–4 August 2017) UN Doc A/CN.4/706 52; 49 49 and draft conclusion 5.3. 194 CRAIG EGGETT Finally, it seems that there is a close relationship between general principles and notions such as equity, justice, and the values of the international community. It is commonly recognised that there exist certain basic values upon which the international legal system is built,196 such as peace and security,197 respect for human rights and humanity,198 and sustainable development.199 These broad values, it has been argued, may lead to the creation of general principles of law.200 Indeed, it seems logical that support for a general principle may be evidenced by its consonance with the basic objectives of the system as a whole and with fundamental ideas of legal logic. C. IDENTIFYING GENERAL PRINCIPLES We turn now to the more practical question of how to identify a general principle. The text of the ICJ Statute itself provides little guidance on how to identify a general principle. It is broadly agreed that the term ‘civilised nations’ should be discarded.201 Indeed, the ILC has confrmed that the phrasing ‘is anachronistic and should no longer be employed. In today’s world, all nations must be considered to be civilized’.202 Going further, in a Separate Opinion in North Sea Continental Shelf, Judge Ammoun asserted that the term ‘is incompatible with . . . the United Nations Charter’.203 Once the term ‘civilised nations’ is discarded, two issues remain: (1) Whose recognition is relevant? and (2) How can it be determined that there is sufcient recognition of a general principle? I. RECOGNITION BY THE ‘COMMUNIT Y OF NATIONS’ The issue of whose recognition is relevant for the identifcation of a general principles touches upon a fundamental question in international law, namely, is the creation of 196 Otto Spijkers, The United Nations, the Evolution of Global Values and International Law (Intersentia 2011); Louis Henkin, ‘International Law: Politics, Values and Functions General Course on Public International Law’ (1990) 216 RdC. 197 Hersch Lauterpacht, ‘The Grotian Tradition in International Law’ (1946) 23 BYIL 1, 51; Hans Kelsen, Peace Through Law (University of North Carolina Press 1944). 198 Antonio Cassese, ‘A Plea for a Global Community Grounded in a Core of Human Rights’ in Antonio Cassese (ed), Realizing Utopia (OUP 2012). 199 Alexander Orakhelashvili, The Interpretation of Acts and Rules in Public International Law (OUP 2008) 182. 200 See, for example, Ginevra le Moli, ‘The Principle of Human Dignity in International Law’ in Andenas and others (n 184). 201 See, for example, Charles Kotuby Jr. and Luke Sobota, General Principles of Law and International Due Process: Principles and Norms Applicable in Transnational Disputes (OUP 2017) 22; Giorgio Gaja, ‘General Principles of Law’ (The Max Planck Encyclopedia of Public International Law, April 2020) <https://opil.ouplaw.com/ display/10.1093/law:epil/9780199231690/law-9780199231690-e1410> accessed 9 August 2023 para 2. 202 ILC, Second report on general principles of law by Marcelo Vázquez-Bermúdez, Special Rapporteur (72nd Session 27 April–5 June and 6 July–7 August 2020) Un Doc A/CN.4/741 2. 203 North Sea Continental Shelf Cases (Germany v Denmark; Germany v Netherlands) (Judgment) [1969] ICJ Rep 3, Separate Opinion of Judge Ammoun, 132. S O U R C E S O F I N T E R N AT I O N A L L A W 195 international law solely the prerogative of States? The ILC seemed to stay broadly in line with a traditional position: ‘For a general principle of law to exist, it must be recognized by the community of nations’.204 The Commission explained that it adopted this phrase because of its use in article 15(2) of the ICCPR,205 which, because of the widespread membership of this treaty, signifes broad acceptance of this terminology.206 II. METHODOLOGY FOR THE RECOGNITION OF GENERAL PRINCIPLES Many of the ILC draft conclusions on general principles are concerned with the approach to be taken when identifying these norms. The approach set out by the Commission is predicated on an initial distinction between two categories of norms, ‘those: (a) that are derived from national legal systems; (b) that may be formed within the international legal system’.207 This distinction is consonant with previous accounts of general principles of law,208 and the ILC diferentiates between the approaches to the ascertainment of each of these categories. 1. General Principles Derived From National Systems Similar to previous attempts,209 the ILC sets out a two-stage approach to this category of general principles, frst ascertaining ‘the existence of a principle common to the various legal systems of the world’ and then ‘its transposition to the international legal system’.210 The frst of these steps is anchored in the idea that comparative law serves as a foundation for the ascertainment of general principles in international law.211 The Commission claims that this need not involve the examination of every legal system of the world. Instead, it proposed a more ‘pragmatic’ approach involving consideration of a representative sample of both the ‘diferent legal families and the regions’ of the world.212 Indeed, such an approach would be a welcome departure from the practice 204 ILC Draft Conclusions (n 194) draft conclusion 2. 205 International Covenant on Civil and Political Rights (adopted 16 December 1966, entered into force 23 March 1976) 999 UNTS 171. 206 ILC Second Report (n 202) 13. 207 ILC Draft Conclusions (n 194) draft conclusion 3. 208 See, for example, Catherine Redgwell, ‘General Principles of International Law’ in Stefan Vogenauer and Stephen Weatherill (eds), General Principles of Law: European and Comparative Perspectives (Hart 2017) 9; Patrick Dailler, Mathias Forteau and Alain Pellet, Droit International Public (8th edn, LGDJ 2009) 380 et seq.; Charles Rousseau, Principes généraux du Droit International Public, Vol. I (Sources) (Pedone 1944) 891. 209 Fabián Raimondo, General Principles of Law in the Decisions of International Criminal Courts and Tribunals (Brill/ Nijhof 2008) 62–74; Miles Jackson, ‘State Instigation in International Law: A General Principle Transposed’ (2019) 30(2) EJIL 391. 210 ILC Draft Conclusions (n 194) draft conclusion 4. 211 For an exploration, see Jaye Ellis, ‘General Principles and Comparative Law’ (2011) 22 EJIL 949. 212 ILC Second Report (n 202) 28. 196 CRAIG EGGETT of courts and tribunals when engaging in comparative law, as there has typically been reliance on just a handful of predominantly European legal systems.213 Second, there is an additional step of transposition into international law. As was noted in the South West Africa Advisory Opinion, rules of domestic law are not transposed ‘lock, stock and barrel, ready-made and fully equipped’ into international law.214 According to the ILC, ‘[a] principle common to the various legal systems of the world may be transposed to the international legal system in so far as it is compatible with that system’.215 A prospective general principle must be compatible with the fundamental principles of international law, such as sovereignty or basic principles in certain felds like law of the sea.216 Further, it is necessary that ‘the conditions exist to allow the adequate application of the principle in the international legal system. This serves to ensure that the principle can properly serve its purpose in international law, avoiding distortions or possible abuse’.217 This requirement seems logical given the fundamental diferences in the nature and structure of international law – as a decentralised and horizontal legal system – when compared with national systems. 2. General Principles Formed Within the International Legal System When it comes to the identifcation of general principles with origins in the international legal system, the ILC states that ‘it is necessary to ascertain that the community of nations has recognised the principle as intrinsic to the international legal system’.218 This is the case if (1) it is widely recognised in treaties and other international instruments, (2) it underlies a general treaty or customary rule, or (3) it is inherent in the basic features and fundamental requirements of the international legal system.219 The frst two of these indicate a close relationship between general principles and the other sources listed in article 38 ICJ Statute, suggesting that the repeated reference to a norm in treaty law or custom can in turn create a general principle. As for the fnal alternative, the ILC provided examples such as uti possidetis juris (Latin: ‘as you possess under law’), or the requirement that States consent to jurisdiction.220 Evidence for the existence of a general principle can be found in a range of diferent instruments and other sources. Further, the ILC specifcally reiterates the role of the 213 See, for example, the approaches taken by some individual ICJ judges: Certain Phosphate Lands in Nauru (Nauru v Australia) (Preliminary Objections) [1992] ICJ Rep 240, Separate Opinion of Judge Shahabudeen, 285; Oil Platforms (Islamic Republic of Iran v United States of America) (Judgment) [2003] ICJ Rep 161, Separate Opinion of Judge Simma. 214 International Status of South West Africa case (Advisory Opinion) [1950] ICJ Rep 128, 148. 215 ILC Draft Conclusions (n 194) draft conclusion 6. 216 ILC Second Report (n 202) [75]–[84]. 217 Ibid 85. 218 ILC Draft Conclusions (n 194) conclusions 7.1. 219 ILC Second Report (n 202) [122]–[158]. 220 Ibid 146–158. S O U R C E S O F I N T E R N AT I O N A L L A W 197 subsidiary means – judicial decisions and academic teachings – in the determination of general principles of both categories.221 D. THE FUNCTIONS OF GENERAL PRINCIPLES Already at the drafting stage of article 38, it was suggested that general principles would have primarily a role to play where there was no applicable treaty or customary rule. This ‘gap-flling’ function is also a prevalent feature of scholarly accounts on general principles.222 The ILC confrmed that the ‘essential function’223 of general principles was to avoid situations of non liquet (Latin: ‘it is not clear’).224 In addition, general principles contribute to the coherence of the international legal system,225 a function that has also been advanced in literature.226 The Commission elaborated that general principles, ‘may serve, inter alia: (a) to interpret and complement other rules of international law; (b) as a basis for primary rights and obligations, as well as a basis for secondary and procedural rules’.227 The frst of these functions seems to follow logically from the references to the links between general principles and the other sources of law in the context of ascertainment. In this regard, the ILC makes explicit reference to the rules of systemic interpretation referred to in article 31(3)(c) VCLT,228 confrming that this provision’s reference to ‘rules of international law’ includes general principles.229 Finally, the ILC’s confrmation that general principles can form a basis for both primary and secondary rules is consonant with the aforementioned legal nature of general principles as source of international law. It should be noted that it is in the development of secondary procedural rules that general principles have been identifed as the most relevant. Scholarly accounts of general principles couple them with ‘international due process’230 and ‘procedural’ norms,231 and international practice confrms that courts and tribunals most frequently make reference to general principles when attempting to answer a procedural question not covered by treaty or customary rule.232 221 ILC Draft Conclusions (n 194) draft conclusions 8 and 9. 222 Hugh Thirlway, The Sources of International Law (OUP 2014) 125; Pellet (n 187) 290; Elias and Lim (n 189) 35–37; Kotuby and Sobota (n 201) 35. 223 ILC, Third report on general principles of law by Marcelo Vázquez-Bermúdez, Special Rapporteur (73rd Session 18 April–3 June and 4 July–5 August 2022) UN Doc A/CN.4/753 [108]. 224 Ibid 39–41. 225 ILC Draft Conclusions (n 194) draft conclusion 11.2. 226 See, generally, the contributions in in Andenas and others (n 184); Eggett (n 187) 149–155. 227 ILC Draft Conclusions (n 194) draft conclusion 11.2. 228 Vienna Convention on the Law of Treaties (adopted 23 May 1969, entered into force 27 January 1980) 1155 UNTS 331, 8 ILM 679. 229 ILC Third Report (n 223) [124]. 230 Kotuby and Sobota (n 201). 231 Forteau (n 190). 232 See, for example, Eggett (n 187) chapter V. 198 CRAIG EGGETT BOX 6.3.3 Example: Pushing the Boundaries of International Law: Judge Cançado Trindade The recognition that general principles can serve as a basis of primary rules indicates significant potential for general principles as a means to expand and modernise the international legal system. If courts and tribunals, particularly the ICJ, embrace this function, it could be that general principles of law serve as a basis of rights and obligations where treaty law and custom do not.233 The late Judge Antonio Augusto Cancado Trindade was an enthusiastic advocate of such a role for general principles, explaining that these norms could serve as a basis for the progressive development of international law to meet contemporary global challenges such as climate change and the protection of human rights.234 233 Ibid. See, for example, Pulp Mills on the River Uruguay (Argentina v Uruguay) (Judgment) [2010] ICJ Rep 14, E.234CONCLUSION Separate Opinion of Judge Cançado Trindade. This section has provided an overview of the basic conceptual aspects of general principles as a source of international law, in light of ongoing debates about their place in the international legal system. General principles are a recognised source of international law and there are many potential instruments and concepts that can be consulting during their ascertainment. It remains to be seen what exactly the full potential of these norms will be, but there is scope for greater reliance on general principles to enhance the functioning of the international legal system as a whole. BOX 6.3.4 Further Reading Further Reading · M Andenas and others (eds), General Principles and the Coherence of International Law (Brill/Nijhoff 2019). · B Cheng, General Principles of Law as Applied by International Courts and Tribunals (CUP 1953). · C Eggett, ‘The Role of Principles and General Principles in the “Constitutional Processes” of International Law’ (2019) 66(2) NILR 197. · I Saunders, General Principles as a Source of International Law: Article 38(1) (c) of the Statute of the International Court of Justice (Hart 2021). §§§ 233 Ibid. 234 See, for example, Pulp Mills on the River Uruguay (Argentina v Uruguay) (Judgment) [2010] ICJ Rep 14, Separate Opinion of Judge Cançado Trindade. S O U R C E S O F I N T E R N AT I O N A L L A W 199 § 6.4 OTHER SOURCES RAFFAELA KUNZ, LUCAS CARLOS LIMA, AND BERNARDO MAGESTE CASTELAR CAMPOS BOX 6.4.1 Required Knowledge and Learning Objectives Required knowledge: Consent; Enforcement; Sources; Treaty Law; Customary International Law Learning objectives: Understanding the secondary sources of international law as listed in article 38 of the ICJ Statute and the limits of the catalogue of formal sources in times of global governance; understanding the role of non-State subjects – such as international organisations – in today’s processes of norm production. A. INTRODUCTION Besides treaty law, customary international law and general principles of law, article 38 of the Statute of the International Court of Justice (ICJ)235 lists two ‘subsidiary means for the determination of rules of law’, namely judicial decisions and ‘the teachings of the most highly qualifed publicists of the various nations’. The word ‘subsidiary’ has predominantly been interpreted as meaning that judicial decisions and teachings are not formal sources themselves, but rather serve as evidence of the existence of the three formal sources.236 In light of this, it has been argued that the term auxiliaire used in the French version more adequately describes the function of jurisprudence and doctrine.237 Rather than providing guidance in a subordinate way if the formal sources give no clear answer, these two means serve as tools to elucidate the existence of norms of international law. However, the distinction between formal sources and subsidiary means is not as clear-cut as often portrayed. For instance, while judicial decisions are listed as ‘subsidiary means’, it is becoming increasingly recognised that in light of the indeterminacy of the law, international norms only come to life once applied in concrete cases. Indeterminacy not only refers to the fact that international legal obligations are often phrased in vague terms, leaving room for divergent interpretations. More fundamentally, language as such is indeterminate, and meaning is only established through interpretation.238 235 Statute of the International Court of Justice (adopted 17 December 1963, entered into force 31 August 1965) 993 UNTS 33. 236 Alain Pellet and Daniel Müller, ‘Art. 38’ in Andreas Zimmermann and others (eds), The Statute of the International Court of Justice: A Commentary (OUP 2019) para 338. 237 Ibid. 238 Ingo Venzke, How Interpretation Makes International Law: On Semantic Change and Normative Twists (OUP 2012) 66. 200 KUNZ, LIMA, AND CASTELAR CAMPOS Consequently, judicial decisions undoubtedly play a considerable role in clarifying and thus also making international law.239 It is also well-established today that further sources exist beyond the ‘list’ contained in article 38. Unilateral declarations are recognised as further ‘traditional’ source of international law. More recently, acts of international organisations, so-called secondary law, and soft law have become increasingly relevant. Both play a crucial role in today’s globalised world. The aim of this chapter is to give an overview of these ‘other’ sources and discuss some of the consequences of the ‘pluralisation’ of the sources doctrine in international law. B. SUBSIDIARY SOURCES (ARTICLE 38(1)(D) ICJ STATUTE) I. JUDICIAL DECISIONS 1. International Judicial Decisions as Sources of Law When an international court or tribunal renders a judicial decision, it becomes binding upon the parties to the dispute. While the bindingness of a specifc judicial decision can be traced to the parties’ consent,240 the general obligation to respect judicial decisions stems from the principle of pacta sunt servanda (Latin: ‘agreements must be kept’).241 An international judicial decision creates lex inter partes (Latin: ‘law between the parties’). The extent to which that decision can create law for the community as a whole is up to debate. Since international judicial decisions are an unavoidable part of the judicial legal system and might perform distinct functions within diferent legal regimes (e.g. trade law, human rights law, international criminal law), it is not possible to generalise the role of decisions as sources of international law.242 The Advisory Committee of Jurists responsible for drafting the Statute of the Permanent Court of International Justice had to address the status of judicial decisions. A proposal to include ‘international jurisprudence as a means for the application and development of law’243 as applicable law was dismissed. Instead, judicial decisions were placed alongside the teachings of publicists in a secondary position. Article 38(1)(d) of the ICJ Statute prescribes that the ICJ (‘the Court’), responsible for deciding in accordance with international law, shall apply judicial decisions as subsidiary 239 Armin von Bogdandy and Ingo Venzke, ‘Beyond Dispute: International Judicial Institutions as Lawmakers’ Special Issue (2011) 12 GLJ 979. 240 On consent, see González Hauck, § 2.2, in this textbook. 241 On pacta sunt servanda, see Fiskatoris and Svicevic, § 6.1.B.IV., in this textbook. 242 ILC, ‘Report of the International Law Commission on the Work of its 72nd Session’ (26 April–4 June and 5 July–6 August 2021) UN Doc A/76/10, Annex ‘Subsidiary means for the determination of rules of international law’. 243 Procès-verbaux [1920] 306. S O U R C E S O F I N T E R N AT I O N A L L A W 201 means for the determination of rules of law. Additionally, the subsidiary application of judicial decisions concerning the other three main sources envisaged in article 38 (treaties, custom, and general principles) is subject to article 59, stating that a decision of the Court ‘has no binding force except between the parties and in respect of that particular case’. Nonetheless, in a legal order predominantly characterised by decentralised methods of normative production, judicial decisions play an important role. While ‘the Court, as a court of law, cannot render judgment sub specie legis ferendae [Latin: ‘of the law to be made’], or anticipate the law before the legislator has laid it down’,244 judicial decisions signifcantly shape the law in certain felds. As put by one author, ‘there has long been no room for doubt that international law has become very much a case law’.245 This has promoted scholarly debate about judicial decisions as formal sources of international law. While some fnd this position unjustifable,246 others defend nuanced approaches like ‘quasi-formal’247 sources, attributing diferent degrees of normativity to judicial decisions, depending on the feld. Less debatable is the fact that judicial decisions are highly authoritative248 within the international legal discourse. While States, international organisations, and other subjects might disagree with a judicial decision, it is binding upon the parties and serves as a guide to the other members of the community as the most appropriate way to perceive the rule. The importance of judicial decisions can be observed not only through the legal value attributed to them by courts or tribunals but also through their impact on the work of codifcation performed by the International Law Commission (ILC),249 the practice of States, or eventually how certain decisions were transformed into treaty law. An illustrative example in this regard can be found in the feld of the law of the sea, in which the ICJ considerably shaped questions such as regarding maritime delimitation.250 However, it is not always possible to identify areas clearly developed on account of judicial decisions. Judicial decisions also exert more subtle, informal infuence on the legal feld, initiating debates or forming a repository of arguments that become unavoidable to understand the development of a certain feld of international law. 244 Fisheries Jurisdiction Case (United Kingdom v Iceland) (Merits) [1974] ICJ Rep 53. 245 Robert Jennings, ‘What Is International Law and How Do We Tell It When We See It?’ (1981) 37 SJIR 41. 246 Alain Pellet, ‘Decisions of the ICJ as Sources of International Law?’ in Gaetano Morelli Lectures Series (International and European Papers 2018). 247 Gerald Fitzmaurice, ‘Some Problems Regarding the Formal Sources of International Law’ in F.M. van Asbeck and others (eds), Symbolae Verzijl (Martinus Nijhof 1958). 248 On this issue, see e.g. Luigi Condorelli, ‘L’autorité de la décision des juridictions internationales permanente’ in Luigi Condorelli (ed), L’optimisme de la raison (IREDIES Pedone 2016) 45. 249 On this topic, see Fernando Lusa Bordin, ‘Refections of Customary International Law: The Authority of Codifcation Conventions and ILC Draft Articles in International Law’ (2014) 63 ICLQ 535. 250 Vaughan Lowe and Antonios Tzanakopoulos, ‘The Development of the Law of the Sea by the International Court of Justice’ in Christian J Tams and James Sloan (eds), The Development of International Law by the International Court of Justice (OUP 2013) 177. 202 KUNZ, LIMA, AND CASTELAR CAMPOS 2. The Authority of a Court’s Own Case Law As seen above, international court decisions, in principle, only bind the parties to the dispute. Consequently, international courts, unlike many of their domestic counterparts, are not legally bound to their own previous decisions. There is no formal rule of precedent (Latin: stare decisis) in international law.251 However, a closer look at the jurisprudence of international courts reveals judicial bodies’ tendency to refer authoritatively to their previous decisions, either to reinforce the interpretation of a given rule or as a shortcut to the legal reasoning previously espoused. In both cases, the court or tribunal contributes to the consolidation of such a rule, apart from the possibility of developing the content of the law. The ICJ stated in 2015 that while its past decisions are not binding on it, ‘it will not depart from its settled jurisprudence unless it fnds very particular reasons to do so’.252 This presumption in favour of adhering to past decisions gives the assurance to future litigants that similar situations will be treated similarly and reafrms important legal values such as equality, predictability, clarity, and, to a certain extent, uniformity, and consistency of international law. Overall, the protection of these values reinforces the legitimacy of an international court and the perception of preservation of the equality of the parties. This might be a good explanation why diferent international courts follow a similar path of self-reference and refer to their previous decisions or even decisions of other international courts.253 3. The Authority of Other Courts’ Case Law Since every international court and tribunal was designed with a unique purpose and according to specifc contextual and social needs, the decisions they render do not carry the same weight. In this regard, there appears to exist a presumption that a certain tribunal’s frst duty is to pay tribute to its own case law before looking beyond its premises. Nonetheless, international courts increasingly draw on external precedents, 251 See, for instance, Mohamed Shahabuddeen, Precedent in the World Court (CUP 2010); Mathias Forteau, ‘Les décisions juridictionnelles comme précédent’ in Société Française pour le Droit International (ed), Le précédent en droit international (Pédone 2016); Makane Moïse Mbengue, ‘Precedent’ in Jean d’Aspremont and Sahib Singh (eds), Concepts for International Law (Edward Elgar 2019) 708. For a more recent reading of the phenomenon, see James Devaney, ‘The Role of Precedent in the Jurisprudence of the International Court of Justice: A Constructive Interpretation’ (2022) 35 LJIL 641. 252 Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Croatia v Serbia) (Merits) [2015] ICJ Rep 3. 253 See, for instance, Eric De Brabandere, ‘The Use of Precedent and External Case Law by the International Court of Justice and the International Tribunal for the Law of the Sea’ (2016) 15 LPICT 24; Yonatan Lupu and Erik Voeten, ‘Precedent in International Courts: A Network Analysis of Case Citations by the European Court of Human Rights’ (2012) 42 BJPolS 413; The ‘Grand Prince’ Case (Belize v France), (Prompt Release, Judgment of 20 April 2001) ITLOS Reports 78; M/V ‘Louisa’ Case (Saint Vincent and the Grenadines v. Kingdom of Spain) (Judgment of 28 May 2013) ITLOS Reports 81; WTO, United States Import Prohibition of Certain Shrimp and Shrimp Products (12 October 1998) WT/DS58/AB/R 67; Al-Adsani v United Kingdom, Judgment, European Court of Human Rights App no 35763/97 (21 November 2001) [60–61]. S O U R C E S O F I N T E R N AT I O N A L L A W 203 a phenomenon called ‘cross-fertilisation’.254 The reference to the case law of other courts follows a logic of speciality, meaning that the specifc function of a judicial body places it in a privileged position for the identifcation, application, and interpretation of certain rules. In this regard, the ICJ has observed that [w]hen the court is called upon . . . to apply a regional instrument for the protection of human rights, it must take due account of the interpretation of that instrument adopted by the independent bodies which have been specifically created, if such has been the case, to monitor the sound application of the treaty in question.255 Cross-fertilisation has acted as a counterforce to the tendencies of fragmentation in international law, since it is highly capable of promoting harmony between international courts on very specifc and often contentious issues. Earlier jurisprudence of a given tribunal may inform future judges of other courts when deciding disputes involving similar factual backgrounds or the ascertainment and interpretation of the same norms. A clear example is the use of regional human rights courts’ case law by the ICJ when it is called upon to resolve disputes relating to human rights.256 In these situations, the fndings of the ‘external’ case law are applied directly as a secondary source of international law (i.e. as authoritative statements of what the law is). Finally, courts also rely on each other regarding procedural questions, including the delimitation of jurisdiction, the conduction of ancillary proceedings, or the behaviour of the parties. This situation reveals not precisely the import of legal ‘fndings’ of an external case law, but a recognition of certain judicial practices as legal rules binding the court given their compatibility with statutory norms and other sources of procedural law (rules of procedure, for instance).257 4. Decisions of Municipal Courts Article 38(1)(d) ICJ Statute does not diferentiate between decisions of international courts and municipal courts. Judicial decisions in general may be considered as a subsidiary source of law and as means for the identifcation of other sources of law.258 However, some particularities of the decisions of municipal courts may be observed in considering them as sources of international law. Contrary to decisions of international courts, those of municipal courts can rarely create obligations binding other States and international organisations, partly due 254 Karin Oellers-Frahm, ‘Multiplication of International Courts and Tribunals and Conficting Jurisdiction – Problems and Possible Solutions’ (2001) 5 UNYB 67; Tullio Treves, ‘Fragmentation of International Law: The Judicial Perspective’ (2007) 23 Comunicazionie studi 821. 255 Ahmadou Sadio Diallo (Rep. of Guinea v. Democratic Republic of Congo) (Merits) [2010] ICJ Rep. 639. 256 Antônio Augusto Cançado Trindade, ‘The Continuity of Jurisprudential Cross-Fertilization in the CaseLaw of International Tribunals in their Common Mission of Realization of Justice’ in The Global Community Yearbook of International Law and Jurisprudence (OUP 2019) 247. 257 Chiara Giorgetti, ‘Cross-Fertilisation of Procedural Law Among International Courts and Tribunals: Methods and Meanings’ in Arman Sarvarian and others (eds), Procedural Fairness in International Courts and Tribunals (BIICL 2015) 223. 258 André Nollkaemper, National Courts and the International Rule of Law (OUP 2011). 204 KUNZ, LIMA, AND CASTELAR CAMPOS to the rules of immunity.259 They may, however, have international legal effects in two situations. First, decisions of municipal courts may be binding on other actors of international law, such as individuals, non-State actors, movements of national liberation, and transnational companies.260 Therefore, decisions of municipal courts may have different degrees of normativity or authority in international law.261 Second, decisions of municipal courts may be considered part of the elements of the formation of customary international law. This is not the same thing as to affirm that decisions of municipal courts are able to ‘create’ international law. Rather, they can contribute to the identification of an emergent rule of customary nature if their content resonates with other samples of practice which, in toto, amount to sufficient consensus concerning its legal character. In the Jurisdictional Immunities of the State case of 2012, the ICJ considered that judgments of national courts would have particular significance in determining the existence of an international custom conferring immunity on States and the scope and extent of such rule. Such decisions were not analysed alone but considered together with statements made by States in the ILC and during the adoption of the Convention on Jurisdictional Immunities of States and Their Property as relevant State practice.262 However, priority is given to decisions of international courts over decisions of municipal courts in the determination of the existence of an international custom. In the Lotus case, for example, the PCIJ only considered decisions of domestic courts after recognising that there were no international decisions to assist in the recognition of the existence of an international norm dealing with the criminal jurisdiction of States in cases of collisions on the high seas.263 There are diferences between varying types of municipal court decisions. Final decisions of higher courts have greater weight than decisions of lower courts in the identifcation of other sources of law. In the Arrest Warrant case, for instance, the ICJ analysed specifcally decisions of national higher courts, such as those of France and the United Kingdom, as State practice to consider the existence of exceptions to the immunity from criminal jurisdiction to Ministers of Foreign Afairs, together with national legislation.264 The role of decisions of municipal courts is even further enhanced when it comes to the identifcation of general principles of law, since their very conceptual framing encompasses the ‘recognition’ by municipal legal orders.265 The assessment of decisions of national courts is part of the comparative analysis of national 259 260 261 262 On immunities, see Walton, § 11, in this textbook. See for instance Filártiga v. Peña-Irala, 630 F.2d 876 (2nd Cir. 1980). Nollkaemper (n 258) 255. Jurisdictional Immunities of the State (Germany v Italy: Greece intervening) (Merits) [2012] ICJ Rep 99, 123. See also ILC, ‘Draft conclusions on identifcation of customary international law’ (2018) UN Doc A/73/10 4. 263 Lotus (France v Turkey), (Merits) PCIJ Rep Series A 10 No 28. 264 Arrest Warrant of 11 April 2000 (Democratic Republic of the Congo v Belgium) (Merits) [2002] ICJ Rep 2. 265 On general principles, see Eggett, § 6.3, in this textbook. S O U R C E S O F I N T E R N AT I O N A L L A W 205 legal systems necessary to determine the existence of a general principle of law. Nevertheless, this element should be considered together with the assessment of national laws and other materials.266 Decisions of municipal courts might also be authoritative within the international legal discourse in several areas. For instance, cases such as the Schooner Exchange (1812) of the US Supreme Court,267 Reference Re Secession of Quebec (1998) from the Supreme Court of Canada,268 and In Re Pinochet (1999) from the House of Lords of the United Kingdom269 are often mentioned in the legal literature to refer to exceptions to the rule of sovereign immunity, the content of the right to self-determination, and the existence of universal jurisdiction, respectively. II. TEACHINGS OF THE MOST HIGHLY QUALIFIED PUBLICISTS Article 38(1)(d) lists ‘the teachings of the most highly qualifed publicists of the various nations’ as second subsidiary means to identify the content of international law. Today, the word ‘scholars’ would likely replace the word ‘publicists’. Often, the literature makes a clear-cut distinction between law-making and scholarly writing. In this view, the role of those writing about international law, as opposed to those making the law, is limited to systematising and providing a better understanding of the law. As one scholar put it, ‘[i]t is obviously not a question of “doctors” dictating the law, but of their infuence on its better understanding’.270 Yet, in reality, the line between law-making and scholarly writing – and in general, between formal and informal sources of international law – is not as clear-cut. In times when the formal sources of international law were much less well documented, scholars played a central role in gathering legal materials, and by doing so arguably also in separating between law and non-law. With the increasing availability of State practice and legal materials in other ways, this role became less relevant. Nonetheless, scholars still wield considerable infuence. Particularly in newer or evolving felds of international law, such as cyberspace law,271 many legal questions are unsolved and courts and other actors applying the law thus turn to the existing literature for guidance and clarifcation. They also contribute to international law-making through collective bodies and expert groups, often mandated by States.272 For instance, the ILC was established by the UN General Assembly (UNGA) with the task of progressively 266 UNGA ‘General Principles of Law: Text of the draft conclusions provisionally adopted by the Drafting Committee on frst reading‘ (12 May 2023) UN Doc A/CN.4/L.982 2, Draft Conclusion 5. 267 The Exchange v McFaddon [1812] 11 US (7 Cranch) 116. 268 Reference re Secession of Quebec [1998] 2 SCR 217. 269 R, ex parte Pinochet v Bartle and ors, Appeal, [1999] UKHL 17. 270 Manfred Lachs, ‘Teachings and Teaching of International Law’ (1976) 151 RdC 161, 212. 271 On international law in cyberspace, see Hüsch, § 19, in this textbook. 272 See on the distinction between State-empowered and other categories of publicists Sandesh Sivakumaran, ‘The Infuence of Teachings of Publicists on the Development of International Law’ (2017) 66 ICLQ 1, 4. 206 KUNZ, LIMA, AND CASTELAR CAMPOS developing and codifying international law (article 1 of the statutes of the ILC).273 According to article 2(1) of its statute, the ILC shall consist of ‘persons of recognized competence in international law’, which, in practice, has often included scholars. Some of the ILC’s work has proven to be highly authoritative and infuential, such as the famous Articles on the Responsibility of States for Internationally Wrongful Acts, which today provide the starting point for most discussions on State responsibility.274 Examples of non–State-sponsored expert groups who proved to be highly authoritative include the group who drafted the San Remo Manual on International Law applicable to Armed Conficts at Sea275 or, more recently, the Tallinn Manuals276 on the application of international law to cyberspace. Repeatedly, attempts were undertaken to ‘measure’ the infuence of scholars on international law. One method to do so is to look at citations by international courts. However, this method is not particularly reliable.277 For example, the ICJ only rarely cites scholarly writings, but there is broad agreement that the infuence of scholars on the ‘World Court’ is greater than it appears.278 The same is true for other courts and institutions. More important than the direct reception, citation, and infuence of scholarship are the manifold indirect ways in which scholars shape and contribute to international law. This begins in the classroom where scholars teach future practitioners, but scholars certainly also exert a certain infuence by criticising, systematising, and ordering the body of international law – a role that has been described as one of ‘grammarians’ within the international legal system.279 C. SOURCES BEYOND THE ICJ STATUTE I. SOFT LAW 1. Definition Soft law refers to those norms in the international legal order that lack legal bindingness. What makes soft norms nonetheless legal and distinguishes them from 273 Statute of the International Law Commission, UNGA Res 174 (II) (21 November 1974) (last amended 18 November 1981). For a recent debate on the role of the ILC the symposium on Völkerrechtsblog, ‘The International Law Commission as an Interpreter of International Law?’ <https://voelkerrechtsblog.org/ symposium/the-role-of-the-ilc/> accessed 20 July 2023. 274 ILC, ‘Responsibility of States for Internationally Wrongful Acts’ (53rd session 23 April–1 June and 2 July–10 August 2001) UN Doc A/RES/56/83 Annex. 275 See e.g. San Remo Manual on International Law Applicable to Armed Conficts at Sea, 12 June 1994 (1995) 309 IRRC 583. 276 Michael Schmitt (ed), Tallinn Manual on the International Law Applicable to Cyber Warfare (CUP 2013); Michael Schmitt (ed), Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (CUP 2017). 277 Sivakumaran (n 272). 278 Pellet and Müller (n 236). 279 Gleider Hernández, ‘The Responsibility of the International Legal Academic. Situating the Grammarian within the “Invisible College”’ in Jean d’Aspremont and others (eds), International Law as a Profession (CUP 2017). S O U R C E S O F I N T E R N AT I O N A L L A W 207 other normative systems is that they contain behavioural guidelines that go beyond purely political or moral declarations.280 According to a narrow view, soft law can only emanate from subjects of international law.281 Examples include non-binding agreements between States, such as the Global Compact for Migration;282 non-binding outcomes of inter-State conferences such as in the feld of the environment the 1972 Stockholm Declaration283 and the 1992 Rio Declaration;284 acts of international organisations lacking bindingness such as the resolutions of the UNGA; and codes of conducts adopted by States or international organisations, for example in international economic law285 or humanitarian law.286 A wider defnition of soft law also includes acts of actors not possessing international legal personality or whose status is not entirely clear, such as selfregulatory instruments of businesses or NGOs.287 This defnition overlaps with what some describe as ‘informal law-making’.288 Such a wider view is preferable – there are countless examples of legislative attempts outside of the traditional diplomatic fora and involving actors other than formal subjects of international law that shape today’s international legal reality.289 2. Function and Contemporary Debates With its defning features, soft law not only falls outside of the category of article 38 ICJ Statute; it seems to fall outside of the category of law altogether. It has therefore caused long-standing and controversial debates in international scholarship. While some praise its fexibility, which might be better suited to adjust to a fast-changing world than formal and slow treaty-making processes, others deem soft law to be undemocratic, a threat to the authority of the law, or simply ‘redundant’.290 Yet, today it seems undeniable that soft law is ‘relevant to international law in some way’.291 On the one hand, it is well recognised that soft law may exert some quasi-legal 280 281 282 283 284 285 286 287 288 289 290 291 Anne Peters and Anna Petrig, Völkerrecht (Schulthess 2020) 48. Daniel Thürer, ‘Soft Law’ (Max Planck Encyclopedia of International Law, March 2009) para 8. Global Compact for Safe, Orderly and Regular Migration (adopted 19 December 2018 UNGA Res 73/195). ‘Report of the United Nations Conference on the Human Environment’ (Stockholm 5–16 June 1972) UN Doc A/CONF.48/Rev.1. ‘Report of the United Nations Conference on Environment and Development’ (Rio de Janeiro 3–14 June 1992) UN Doc A/CONF.151/26 (Vol I). OECD, OECD Guidelines for Multinational Enterprises on Responsible Business Conduct (OECD 2023). See e.g. San Remo Manual on International Law Applicable to Armed Conficts at Sea (n 275). See e.g. Oversight Board, ‘Meta Oversight Board Charter’ (February 2023) <https://oversightboard.com/ attachment/494475942886876/> accessed 10 August 2023. Joost Pauwelyn, Ramses A Wessels, and Jan Wouters (eds), Informal International Lawmaking (OUP 2012). See the numerous cases studies in Joost Pauwelnyn and others, Informal International Lawmaking: Case Studies (Torkel Opsahl Academic EPublisher 2013). Jan Klabbers, ‘The Redundancy of Soft Law’ (1996) 65 Nordic Journal of International Law 167. For a good overview of the debate, see Jean d’Aspremont and Tanja Aalberts, ‘Which Future for the Scholarly Concept of Soft International Law? Editors’ Introductory Remarks’ (2012) 25 LJIL 309. Jaye Ellis, ‘Shades of Grey: Soft Law and the Validity of Public International Law’ (2012) 25 LJIL 313, 318. 208 KUNZ, LIMA, AND CASTELAR CAMPOS efects: soft standards can ‘harden’ over time – they may be taken up in a later treaty or mature into opinio juris and therefore catalyse the formation of customary international law. Another way soft law becomes legally relevant is as a guideline for interpretation of ‘hard’ law, with UNGA resolutions being an important example.292 On the other hand, soft standards can have rather ‘hard’ and tangible consequences despite not being legally binding. Because of the factual relevance of soft law, in some States such as Switzerland, attempts are being undertaken to introduce stronger parliamentary oversight for soft law instruments, traditionally reserved to formal treaty-making.293 Currently, the relevance of soft law even seems to increase. Several studies have constated a ‘treaty fatigue’ and shown that the conclusion of treaties over the last years has stagnated.294 By way of example, while in the period between 1950 and 2000, each decade around 35 new multilateral treaties were concluded, this number signifcantly dropped in the following decade and currently even stopped.295 Given the difculties to reach consensus on binding obligations, the relevance of soft instruments arguably grows. Regardless of its advantages and disadvantages, what seems clear today is ‘that soft law is a reality and instrument of contemporary governance that cannot be wished away’.296 The importance of soft standards not only evidences the pluralisation of the sources of international law, but also of the actors behind these instruments.297 The concept of soft law is thus a prime example showing that both the classic notions of sources and of actors in international law do not fully capture the international legal reality anymore. II. ACTS OF INTERNATIONAL ORGANISATIONS Acts or resolutions of international organisations are often listed among possible sources of international law besides the traditional categories of sources listed in article 38(1) ICJ Statute. This consideration refects the growing importance of the activities and acts of international organisations in times of global governance.298 New procedures of collective action within international organisations have been developed in an approach paralleling the law-making process of domestic law. For 292 Rossana Deplano, Empirical and Theoretical Perspectives on International Law: How States Use the UN General Assembly to Create International Obligations (CUP 2022). 293 For an overview, see Anna Petrig, ‘Democratic Participation in International Lawmaking in Switzerland After the “Age of Treaties”’ in Helmut Aust and Thomas Kleinlein (eds), Encounters Between Foreign Relations Law and International Law (CUP 2021) 180. 294 Joost Pauwelyn, Ramses A Wessel, and Jan Wouters, ‘When Structures Become Shackles: Stagnation and Dynamics in International Lawmaking’ (2014) 25 EJIL 733, 739; see also Jan Wouters, ‘International Law, Informal Law-Making, and Global Governance in Times of Anti-Globalism and Populism’ in Heike Krieger, Georg Note, and Andreas Zimmermann (eds), The International Rule of Law: Rise or Decline? (OUP 2019). 295 Wouters (n 294) 251. 296 D’Aspremont and Aalberts (56) 309. 297 On the pluralisation of actors in international law, see Engström, introduction to § 7, in this textbook. 298 On international organisations, see Baranowska, Engström, and Paige, § 7.3, in this textbook. S O U R C E S O F I N T E R N AT I O N A L L A W 209 instance, the UN Security Council (UNSC) adopted a new form of procedure creating general obligations for all States to prevent the commission or the fnancing of terrorist acts.299 It is possible to consider, therefore, that a new way of creating international rules beyond the classic means has emerged from the operation of international organisations, especially the United Nations. On the other hand, such characterisation presents some problems, as discussed in the following. 1. Acts of International Organisations as a Distinct Source of International Law a) Acts of International Organisations as Formal Source of International Law Acts of international organisations can serve as a formal source of rights and obligations depending on the actor concerned. They can be divided into two categories. The frst consists of acts by organs of the organisation externally directed to States or other organisations, such as recommendations, declarations, or decisions. The second type includes internal measures by organs of the organisation in fulflment of their functions according to the constitutive instrument, determining for instance the budget of the organisation, the creation or composition of an organ, and other procedural aspects. As this second type of act may establish rights and obligations in the internal law of organisations for diferent organs, individuals, and entities, it may be considered a formal source of law for such actors. This is the case of the decisions of the United Nations Dispute Tribunal, which are binding upon the parties of disputes opposing individuals and the UN Secretary-General or a specialised agency.300 The frst type of instrument may be considered as a distinct formal source of international law creating legal obligations for the parties concerned.301 Member States are obliged to comply with binding resolutions by virtue of an obligation assumed through the constitutive treaty, not because such resolutions create direct obligations for them. This is the case of decisions of the UNSC based on article 25 and Chapter VII of the UN Charter302 and some acts emanating from the European Union based on article 288 of the Treaty on the Functioning of the European Union.303 In this sense, it could be argued that the normative force of resolutions of international organisations is linked to conventional obligations created by treaties, a traditional source of international law. It is claimed that the UNSC on some occasions has adopted a sort of ‘law-making procedure’ by imposing general obligations to all UN member States regarding 299 UNSC Res 1373 (28 September 2001) UN Doc S/RES/1373. 300 UNGA Res 62/253 (17 March 2009) UN Doc A/RES/62/253 (Statute of the United Nations Dispute Tribunal) article 11(3). See also Efect of Awards of Compensation Made by the United Nations Administrative Tribunal (Advisory Opinion) [1954] ICJ Rep 47. 301 On the formal/material distinction, see Eggett, § 6.B.II., in this textbook. 302 Charter of the United Nations (adopted 26 June 1945, entered into force 24 October 1945) 1 UNTS 16, articles 25 and 39–51. 303 Consolidated version of the Treaty on the Functioning of the European Union [2012] OJ C326/47, article 288. 210 KUNZ, LIMA, AND CASTELAR CAMPOS specifc matters. In general, the Council adopts decisions binding on the UN member States which are instrumental to deal with a situation characterised by it as a threat to the peace, a breach of the peace or an act of aggression, according to article 39 of the UN Charter.304 In some resolutions, nonetheless, the UNSC seem to have stated obligations of abstract nature, that is, not limited to a particular situation or dispute, such as general obligations concerning the suppression of terrorist acts305 and the limitation of certain types of weapons.306 In such cases, the UNSC appears to impose on member States obligations that are found in conventions to which they have not necessarily expressed their consent. Since such obligations have general application and are not limited to a particular situation or dispute, they appear to have been the result of a law-making process by the UNSC. Yet in this case, the resolutions do not act as formal sources of obligations since their binding force is based on the action of the UNSC under Chapter VII of the UN Charter, although their legality in relation to the Charter and the powers of the UNSC may be questioned.307 b) Acts of International Organisations as Material Source of International Law Resolutions of international organisations can be viewed not merely as formal sources of obligations but also as evidence of the existence of a rule of customary international law. In such cases, these resolutions function as material sources of international law.308 The ICJ occasionally analyses UNGA Resolutions to determine the existence of a rule of customary international law,309 considering that although not binding, they may ‘provide evidence important for establishing the existence of a rule or the emergence of an opinio juris’.310 Such an approach was adopted in the Nicaragua case, where the Court interpreted the consent of the United States and Nicaragua expressed at the moment of the adoption of UNGA Resolution 2625 (24 October 1970, establishing the Friendly Relations Declaration)311 as ‘an acceptance of the validity of the rule or set of rules declared by the resolution’.312 UNGA Resolutions are also sometimes considered to reflect legal rules of international law due to the almost universal representation of the international 304 305 306 307 308 309 310 311 312 Stefan Talmon, ‘The Security Council as World Legislature’ (2005) 99 AJIL 175–193. UNSC Res 1373 (28 September 2001) UN Doc S/RES/1373. UNSC Res 1540 (28 April 2004) UN Doc S/RES/1540. James Crawford, ‘Chance, Order, Change: The Course of International Law’ (2013) 365 RdC 17, 312–313. On the formal/material distinction, see Eggett, § 6.B.II., in this textbook. On customary international law, see Stoica, § 6.2, in this textbook. Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion) [1996] ICJ Rep 226, 254–255 [para 70]. UNGA Res 2625 (XXV) (24 October 1970). Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) (Merits) [1986] ICJ Rep 14, 99–100 [para 188]. S O U R C E S O F I N T E R N AT I O N A L L A W 211 community of States in the organ. Instances include other declarations besides the Friendly Relations Declaration,313 such as the Universal Declaration of Human Rights of 1948,314 the Declaration on the Granting of Independence to Colonial Countries and Peoples of 1960,315 and the Declaration of Legal Principles Governing the Activities of States in the Exploration and Uses of Outer Space of 1963.316 In the Chagos Advisory Opinion, the ICJ found that the Declaration on the Granting of Independence to Colonial Countries and Peoples ‘has a declaratory character with regard to the right to self-determination as a customary norm’ and clarified the content and scope of the right to self-determination, representing a ‘defining moment in the consolidation of State practice on decolonization’.317 Resolutions may also be relevant in the interpretation of international treaties and even constitute subsequent practice for the purpose of treaty interpretation.318 In the Whaling case, for instance, the ICJ considered that resolutions from the International Whaling Commission may be relevant for the interpretation of the International Convention for the Regulation of Whaling when adopted by consensus or by a unanimous vote, even not having a binding efect.319 2. Acts of International Organisations Beyond the Concept of Legal Source of Rights and Obligations The classic defnition of sources of international law may be insufcient to apprehend the legal signifcance of acts of international organisations to international law as they can hardly be considered as an independent category of sources of international law for not being able to create autonomously rights and obligations for States. Traditionally, it is recognised that acts of international organisations usually are the result of a political compromise that does not intend to create legal obligations by itself. This understanding is shared by the practice of the ICJ, which often rejects the claim that resolutions create legal obligations for States that consent to them. For instance, in the Nicaragua case, the Court rejected the claim that a resolution of the Meeting of Consultation of Ministers of Foreign Afairs of the Organization of American States had established a legal obligation for Nicaragua regarding its domestic policy.320 In the Access to the Pacifc Ocean case of 2012, the Court rejected the claim that resolutions 313 314 315 316 317 UNGA Res 2625 (XXV) (24 October 1970). UNGA Res 217A (III) (10 December 1948). UNGA Res 1514 (XV) (14 December 1960). UNGA Res 1962 (XVIII) (13 December 1963). Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965 (Advisory Opinion) [2019] ICJ Rep 95 [paras 150–153]. 318 Michael C Wood, The Interpretation of Security Council Resolutions (1998) 2 Max Planck Yrbk UN L 73–95, 91–92. 319 Whaling in the Antarctic (Australia v Japan: New Zealand intervening) [2014] ICJ Rep 226, 248 [para 46]. See also Nicaragua (n 78) [para 188]. 320 Nicaragua (n 78) [para 261]. 212 KUNZ, LIMA, AND CASTELAR CAMPOS adopted by the General Assembly of the Organisation of the American States had created a legal obligation for Chile to negotiate Bolivia’s access to the Pacifc Ocean, even if adopted with its consent.321 Nevertheless, the legal importance of resolutions of international organisations goes beyond the legal efects traditionally assigned to them. Often such acts afect the behaviour of States and other international actors even without the establishment of legally binding rules, which may be observed in the context of the role of international organisations in global governance. It is increasingly common for international organisations to adopt resolutions containing standards, practices, and procedures which provide a normative framework for the exercise of public authority in several areas of international law regardless of their binding character. Such acts, which often are classifed as ‘soft law’, sometimes are preferred over traditional sources of international law for the facility in their creation and fexibility. This may be seen, for instance, in the regulatory function of the food standards issued by the Codex Alimentarius Commission, the Code of Conduct for Responsible Fisheries of the UN Food and Agriculture Organisation (FAO), and the OECD Guidelines for Multinational Enterprises, all of which with signifcant regulatory form even without binding character.322 Another important example concerns the role of the World Health Organization (WHO) in global health governance, especially regarding the COVID-19 pandemic. The coordination between public and private international actors in the fght against the virus was done by the WHO not only through binding rules provided for by the International Health Regulations (2005) but also by temporary and nonbinding recommendations adopted on advice of an Emergency Committee composed by experts of diferent felds.323 III. UNILATERAL DECLARATIONS Besides soft law and acts of international organisations, unilateral declarations are often discussed as a further source beyond article 38 of the ICJ Statute. The question is whether declarations States make towards other States or the international community, for example a promise to act in a certain way, may deploy legal efects. In other words, can States be legally bound by statements or announcements they made? In the Nuclear Tests case,324 the ICJ has answered this question in the positive under certain conditions, deducing the legal bindingness from the principle of good faith, a general principle under article 38(1)(c) ICJ Statute. In this case, the ICJ among other things had to determine whether France was 321 Obligation to Negotiate Access to the Pacifc Ocean (Bolivia v Chile) (Merits) [2018] ICJ Rep 507, 562 [para 171]. 322 See in special the analysis of such regulations by Gefon Schuler and others (eds), The Exercise of Public Authority by International Institutions: Advancing International Institutional Law (Springer 2010). 323 Armin von Bogdandy and Pedro Villarreal, ‘International Law on Pandemic Response: A First Stocktaking in Light of the Coronavirus Crisis’ (2020) MPIL Research Paper 07/2020. See also Mateja Steinbrück Platise, ‘The Changing Structure of Global Health Governance’ in L Vierck, P Villarreal, and A Weilert (eds), The Governance of Disease Outbreaks (Nomos 2017) 83–111. 324 Nuclear Tests Case (Australia v. France) (Merits) [1974] ICJ Rep. 253. See already Legal Status of Eastern Greenland (Denmark v. Norway) PCIJ Ser A/B No 53. S O U R C E S O F I N T E R N AT I O N A L L A W 213 bound by its announcements in various public statements to refrain from carrying out further atmospheric nuclear tests in the South Pacifc region. In order not to deduce legal efects from merely political statements, the ICJ developed three criteria: • The declaration must have been made by the competent authority in a framework that indicates seriousness; • The declaration must be sufciently specifc; and • It must indicate the intention to be legally bound.325 A specifc form is not required according to the Court; this means that also oral statements can deploy legal efects. Also further unilateral acts of States can deploy certain legal efects, as discussed in other chapters. By way of example, the protesting State under the persistent objector doctrine can avoid being legally bound by emerging customary international law;326 also acts of recognition by States may deploy legal efects.327 D. CONCLUSION This chapter has shown that further sources of international law beyond article 38 of the ICJ Statute exist, and that they are in fact highly relevant. In times of global governance, the decisions of international courts, resolutions of international organisations, and soft law regulate many aspects of our lives. This pluralisation of the sources of international law to some extent refects the pluralisation of its actors. This development challenges the formal distinction between law and non-law, showing that ‘the universe of norms is larger than the universe of law’328 and once more raising the fundamental question: is it international law or not, and does it even matter?329 According to voices from the New Haven School, what ultimately counts is the infuence of norms on behaviour of States, and not their form.330 However, as important as informal sources of international law might be, the distinction between law and non-law is certainly not entirely redundant. Even though international courts might take other sources into account, they rule on the basis of formal law. The pluralisation of the sources of international law also leads to new challenges for the democratic legitimisation of international law, as the debate in Switzerland about stronger parliamentary involvement in the process of adopting soft law shows.331 Even though touching upon some of the oldest debates in international law, the sources doctrine certainly has not lost any of its currency. 325 Nuclear Tests Case (n 90) [paras 42–46]. See also ILC, ‘Guiding Principles Applicable to Unilateral Declarations of States Capable of Creating Legal Obligations (Final Outcome)’ UN Doc A/61/10 para 176. 326 On the persistent objector doctrine, see Stoica, § 6.2.C.II., in this textbook. 327 On recognition, see Green, § 7.1.C.I.1., in this textbook. 328 See Jost Pauwelyn, ‘Is It International Law or Not, and Does it Even Matter?’ in Joost Pauwelyn, Ramses Wessel, and Jan Wouters (eds), Information International Lawmaking (OUP 2012) 125. 329 Ibid. 330 See e.g. Monica Hakimi, ‘The Work of International Law’ (2017) 58 Harvard International Law Journal 1. 331 See above n 293. 214 KUNZ, LIMA, AND CASTELAR CAMPOS BOX 6.4.2 Further Readings Further Readings · S Besson, ‘Theorizing the Sources of International Law’ in S Besson and J Tasioulas (eds), The Philosophy of International Law (OUP 2010). · G Guillaume, ‘The Use of Precedent by International Judges and Arbitrators’ (2011) 2(1) JILDS 5. · C Tams, ‘The World Court’s Role in the International Law-Making Process’ in J Delbrück and others (eds), Aus Kiel in die Welt: Kiel’s Contribution to International Law. Essays in Honour of the 100th Anniversary of the Walther Schücking Institute for International Law (Duncker und Humblot 2014). · A Tzanakopoulos, ‘Domestic Judicial Lawmaking’ in C Brölmann and Y Radi (eds), Research Handbook on the Theory and Practice of International Lawmaking (Edward Elgar 2016). · G Hernández, ‘International Judicial Lawmaking’, in C Brölmann and Y Radi (eds), Research Handbook on the Theory and Practice of International Lawmaking (Edward Elgar 2016). §§§