Defense Secretary Mattis resigns in protest with scathing letter rejecting Trump's worldview

Defense Secretary James Mattis resigned one day after Trump's Syria withdrawal announcement, submitting a two-page letter that amounted to a point-by-point rejection of Trump's approach to foreign policy and alliances. Mattis wrote "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." The letter emphasized that "our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships" and stressed the importance of treating allies with respect. Mattis, widely viewed as a stabilizing force and "adult in the room," became the first defense secretary to resign in protest since 1968. Trump later became furious at the letter's implicit rebuke and accelerated Mattis's departure, cutting short his intended transition period.

"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." — December 20, 2018 resignation letter from Defense Secretary James Mattis after Syria withdrawal decision