Vice Chairman of the Joint Chiefs of Staff Adm. James A. Winnefeld Jr. testifies before the House Armed Services Committee during a hearing on Nuclear Deterrence in the 21st Century, in Washington, June 25, 2015. Winnefeld joined Deputy Secretary of Defense Robert O. Work and Deputy Secretary of Energy Elizabeth Sherwood-Randall as witnesses during the military nuclear posture hearing on Capitol Hill. (DoD photo by Army Staff Sgt. Sean K. Harp/Released)