Retired Army Gen. Martin E. Dempsey, 18th chairman of the Joint Chiefs of Staff, listens as Marine Corps Gen. Joseph F. Dunford Jr., the current chairman, delivers remarks during the change of responsibility ceremony for the senior enlisted advisor to the chairman of the Joint Chiefs of Staff on Joint Base Myer-Henderson Hall, Va., Dec. 11, 2015. Army Command Sgt. Maj. John W. Troxell became the third senior enlisted advisor to the chairman of the Joint Chiefs of Staff, while Marine Corps Sgt. Maj. Bryan B. Battaglia retired after 36 years in service. DoD photo by Navy Petty Officer 2nd Class Dominique A. Pineiro