Reaction from both sides of the aisle is coming in to the sudden “resignation” of Defense Secretary James Mattis. As Senator Chris Murphy (D-CT) put it, “A Secretary of Defense quitting over a public disagreement with a President whose foreign policy he believes has gone off the rails is a national security crisis. No way around it.”

Here is what some other prominent politicians are saying:

Senator Marco Rubio (R-FL): Just read Gen. Mattis resignation letter. It makes it abundantly clear that we are headed towards a series of grave policy errors which will endanger our nation, damage our alliances & empower our adversaries.

I hope we who have supported this administration’s initiatives over the last two years can persuade the President to choose a different direction. But we must also fulfill our constitutional duty to conduct oversight over the policies of the executive branch.

Senator Lindsey Graham (R-SC): It is with great sadness that I was informed of the resignation of General Mattis. He is one of the great military leaders in American history. He should be proud of the service he has rendered to President @realDonaldTrump and our nation.

Senate Minority Leader Nancy Pelosi (D-CA):

Senator Mark Warner (D-VA): This is scary. Secretary Mattis has been an island of stability amidst the chaos of the Trump administration. As we’ve seen with the President’s haphazard approach to Syria, our national defense is too important to be subjected to the President’s erratic whims.

Senator Ben Sasse (R-NE): This is a sad day. General Mattis was giving advice POTUS needs to hear. Mattis rightly believes that Russia & China are adversaries, and that we are at war with jihadists across the globe who plot to kill Americans. Isolationism is a weak strategy that will harm Americans that will harm America and America’s allies. Radical jihadists are still at war with us, and NO, MR PRESIDENT, ISIS is not gone. It’s not true — and just proclaiming it doesn’t make it so.

Rep. Adam Kinzinger (R-IL): I admire Secretary Mattis. His service has been one of honor & respect. His resignation is an act of patriotism, standing for our American principles above all else.