Mattis resigns after clash with Trump Jim Mattis, the U.S. defence secretary, is the fourth member of President Trump’s cabinet to resign or be forced out in less than two weeks Jim Mattis, Secretary of Defence: Retired four-star Marine general quits December 20, one day after President Trump declares victory over so-called Islamic State on Twitter and announces withdrawal of 2,000 U.S. troops from Syria and roughly 7,000 troops from Afghanistan Ryan Zinke, Secretary of Interior: Quits December 15 amid ethics investigations into his business dealings, travel and policy decisions Nick Ayers, Chief of staff to vice president: Quits December 9 after refusing Trump’s offer to be his new chief of staff John F. Kelly, White House chief of staff: Quits December 8 amid rumours that he found Trump impossible to control Sources: Associated Press, Reuters Pictures: Associated Press © GRAPHIC NEWS