Updated on December 20 at 7:35 p.m. ET
Secretary of Defense James Mattis is resigning over conflicts with President Donald Trump concerning American policy overseas—the highest-profile official to quit the administration over disagreements of principle with the president.
In a resignation letter, Mattis laid out a series of differences with Trump, who he said deserved to have a secretary of defense who was aligned with him. Mattis cited the importance of international alliances and partnerships, constraining Russia, and maintaining an American military presence overseas. By the standard of resignation letters, which typically flatter a president and avoid direct conflict, the missive is a scathing rebuke.
“I believe we must be resolute and unambiguous in our approach to those countries whose strategic interests are increasingly in tension with ours,” Mattis wrote. “It is clear that China and Russia, for example, want to shape a world consistent with their authoritarian model—gaining veto authority over other nations’ economic, diplomatic, and security decisions—to promote their own interests at the expense of their neighbors, America and our allies.”
The news comes a day after Trump said that U.S. troops would leave Syria, a move the Pentagon opposed. The president announced Mattis’s exit in a tweet. “General Jim Mattis will be retiring, with distinction, at the end of February, after having served my Administration as Secretary of Defense for the past two years,” Trump wrote. “A new Secretary of Defense will be named shortly. I greatly thank Jim for his service!”