Defense Secretary Ash Carter stands while honors are played during the Marine Corps passage-of-command ceremony on Marine Barracks, Washington, D.C., Sept. 24, 2015. Marine Corps Gen. Joseph F. Dunford relinquished command to Marine Corps Gen. Robert B. Neller. Gen. Dunford will take over as Chairman of the Joint Chiefs of Staff. DoD photo by Army Staff Sgt. Sean K. Harp