In a two-page letter to the president, Mattis laid out his convictions on the value of US leadership in strategic alliances, including the North Atlantic Treaty Organization and the 74-nation coalition to defeat Islamic State. His letter also suggested differences with Trump over the president’s handling of the challenges from Russia and China.
(Dec 21): Defense Secretary Jim Mattis announced his resignation on Thursday, citing differences over policy with Donald Trump, a day after the president abruptly called for the withdrawal of American forces from Syria.
Mattis informed the president of his decision in a meeting earlier in the afternoon in which the two discussed policy differences that have included the president’s decision to pull out of Syria, said a White House official. Mattis’s departure didn’t cause the president to rethink his decision on Syria, the official added.

