Support WBURFormer Defense Secretary Mattis Issues Stunning Rebuke Of TrumpScott NeumanJune 04, 2020 SharePresident Trump in October 2018 is joined by (from left) Army Chief of Staff Gen. Mark Milley, Defense Secretary Jim Mattis, Chairman of the Joint Chiefs of Staff Gen. Joe Dunford and Marine Corps Commandant Gen. Robert Neller. (AP)