AdvertisementBook ReviewIn Book, Former Defense Chief Mattis Sideswipes President Trump's Leadership SkillsAugust 28, 2019David WelnafacebookEmailJames Mattis, then U.S. secretary of defense, leaves a news conference following a meeting about U.S.-China diplomacy and security at the State Department in Washington, D.C., in June 2017. Mattis' new book, Call Sign Chaos, implies criticism of President Trump without taking direct shots at him. (Bloomberg via Getty Images)