From left, Chairman of the Joint Chiefs of Staff U.S. Army Gen. Martin E. Dempsey, Chief of Naval Operations U.S. Navy Adm. Jonathan Greenert and Chief of Staff of the U.S. Air Force Gen. Mark A. Welsh listen as U.K. Secretary of State for Defense Philip Hammond talks during a Defense Chiefs Strategic Dialog with the U.S. Joint Chiefs of Staff and their U.K. counterparts in London, June 10, 2014. (DoD photo by Mass Communication Specialist 1st Class Daniel Hinton, U.S. Navy/Released)