It's time to draw the line: any attempt by President Trump to interfere with Special Counsel Robert Mueller's investigation would provoke a constitutional crisis.

That means:

- Firing Robert Mueller or top FBI or DOJ brass overseeing the investigation.

- Pardoning key witnesses in an effort to shield them from accountability

- Any other attempt to shut down the investigation

Any of these actions would be a gross abuse of power and a flagrant violation of Executive branch responsibilities and authorities. These are red lines, and we simply cannot allow them to be crossed.

In recent weeks, a growing chorus of voices in Congress, the media, and the White House have begun pushing a coordinated narrative undermining the credibility of the Special Counsel’s investigation and the FBI itself.

These statements are reckless. They are inappropriate. And they are extremely worrying.

While the President has said he is not considering removing Special Counsel Mueller, the President’s track record on this front is a source of concern. I’m certain many of my colleagues believed that he wouldn’t possibly fire Mr. Comey, either.

Firing Mr. Mueller or any of the top brass involved in this investigation would call into question this Administration’s commitment to the truth and the rule of law.

In the United States of America, no one is above the law. Not even the President.

Congress must make clear to the President that firing the Special Counsel, or interfering with his investigation by issuing pardons of essential witnesses, is unacceptable, and would have immediate and significant consequences.

I hope my concerns are unfounded, but there are troubling signs. It is critical that we as elected officials, and as citizens, speak up against these threats now…before it is too late.