Should President Trump fire special counsel Robert Mueller in the middle of his investigation into Russian collusion in the 2016 election, it will be considered a "gross abuse of power" and Congress will act accordingly, Sen. Mark Warner (D-VA) warned him Wednesday on the Senate floor.

"Any attempt by this President to remove special counsel Mueller from his position or to pardon key witnesses in any effort to shield them from accountability or shut down the investigation would be a gross abuse of power and a flagrant violation of executive branch responsibilities and authorities," Warner said. "These truly are red lines and simply cannot allow them to be crossed." "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," he added. (CNN)

Warner is the highest ranking Democrat on the Senate Intelligence Committee. In March, he and his Republican colleague Richard Burr put on a convincing display of camaraderie as they promised to get to the bottom of Russia's interference in our elections.

In the past several months, Trump has dismissed the special counsel probe as a "witch hunt." He has reason to be skeptical of the probe in recent days, especially after FBI agent Peter Strzok was found to have sent scathing anti-Trump texts to his mistress last year. He was removed from the investigation, but officials were grilled about the agency's integrity in light of the discovery.

Still, last week Trump looked the press right in the eye and said "no" he is not going to fire Mueller.