Oath of Enlistment Defense Secretary Ash Carter performs an oath of enlistment ceremony during a visit to the Chicago Military Entrance Processing Station in Chicago, July 28, 2016. DoD photo by Air Force Tech. Sgt. Brigitte N. Brantley SHARE: Download: Full Size (1.45 MB) Credit: Brigitte N. Brantley VIRIN: 160728-D-XT155-004.JPG Photo Gallery