Leader Meeting Defense Secretary Jim Mattis, second from left, meets Army Command Sgt. Maj. John W. Troxell, right, senior enlisted advisor to the chairman of the Joint Chiefs of Staff, at the Pentagon during his first full day as secretary, Jan. 21, 2017. Looking on are Deputy Defense Secretary Bob Work, left, and Air Force Gen. Paul Selva, vice chairman of the Joint Chiefs of Staff. DoD photo by D. Myles Cullen SHARE IMAGE: Download Image: Full Size (0.45 MB) Tags: bob work, paul selva, JIm Mattis, john troxell, Soldiers, Army, SecDef, DepSecDef, Joint Chiefs, Senior Enlisted Advisor, SEAC, AIR FORCE, Vice Chairman, Airmen Photo By: D. Myles Cullen VIRIN: 170121-D-VO565-008.JPG Photo Gallery