Jim Mattisthe U.S. Secretary of Defense, announced Thursday afternoon he would retire at the end of February.

Mattis, a four-star Marine general, resigned over his opposition to President Donald Trump‘s announcement on Wednesday that the White House decided to withdraw roughly 2,000 U.S. troops from Syria, where the military has been fighting the Islamic State (ISIS).

Mattis is the latest White House official to leave the Trump administration after finding himself at odds with the president on several issues.

“One core belief I have always held is that our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships,” Mattis wrote. in his resignation letter, which was released by the Pentagon. “Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position,” he wrote.

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Trump also announced Mattis’ resignation on Twitter Thursday evening, and thanked him for his service.


Trump received severe criticism from many lawmakers, including Republicans, for his decision regarding troops in Syria. GOP lawmakers like Sen. Lindsey Graham and Sen. Ben Sasse were among those who condemned the move, with some even meeting with Vice President Mike Pence Thursday to rebuke it.

Mattis was widely regarded by many as the most mature person in the Administration — similarly to how fellow veteran and former chief of staff John Kelly was viewed — and this appeared to anger Trump, who once called Mattis a Democrat.

Mattis also reportedly dragged his feet on many proposals Trump pushed since taking office nearly two years ago, including the transgender military ban and the Space Force.