Members of the official party stand at the start of the change-of-command ceremony for the North American Aerospace Defense Command and U.S. Northern Command at Peterson Air Force Base, Colo., May 13, 2016. From left are Defense Secretary Ash Carter; Canadian Defense Minister Harjit Sajjan; U.S. Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff; Canadian Army Gen. Jonathan Vance, chief of the Canadian defense staff; Navy Adm. Bill Gortney, outgoing commander of NORAD and Northcom; and incoming commander Air Force Gen. Lori J. Robinson. DoD photo by Navy Petty Officer 2nd Class Dominique A. Pineiro