Army Command Sgt. Maj. John W. Troxell, senior enlisted advisor to the chairman of the Joint Chiefs of Staff, addresses general and flag officers during a National Defense University Capstone course at Fort Lesley J. McNair in Washington, D.C., July 12, 2016. The course aims to make general and flag officers more effective in planning and employing U.S. forces in joint and combined operations. DoD photo by Navy Petty Officer 2nd Class Dominique A. Pineiro