160415-D-DT527-503 SOUTH CHINA SEA (April 15, 2016) Secretary of Defense (SECDEF) Ash Carter and Philippine Secretary of National Defense Voltaire Gazmin (right) walk as they tour the aircraft carrier USS John C. Stennis (CVN 74) as it sails the South China Sea April 15, 2016. Carter is visiting the Philippines to solidify the rebalance to the Asia-Pacific region. (U.S. Air Force photo by Senior Master Sgt. Adrian Cadiz/Released)