Pentagon Visit Defense Secretary James N. Mattis; Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff; and Army Command Sgt. Maj. John W. Troxell, the chairman's senior enlisted advisor, meet with Cooper Smith and his family during an official visit at the Pentagon, April 2, 2018. DoD photo by Army Sgt. Amber I. Smith SHARE: Download: Full Size (0.34 MB) Credit: Sgt. Amber I. Smith VIRIN: 180402-D-SV709-0100.JPG Photo Gallery