Mattis Handshake Defense Secretary James N. Mattis congratulates Air Force Gen. Terrence J. O’Shaughnessy after he took command of North American Aerospace Defense Command and U.S. Northern Command during a ceremony at Peterson Air Force Base, Colo., May 24, 2018. Photo courtesy U.S. Northern Command SHARE IMAGE: Download Image: Full Size (0.11 MB) Tags: NORAD, James N. Mattis, SecDef, Northcom, Air Force, U.S. Northern Command Photo By: Photo courtesy U.S. Northern Command VIRIN: 180524-F-ZZ999-046.JPG Photo Gallery