Chairman of the Joint Chiefs of Staff U.S. Army Gen. Martin E. Dempsey, center right, and commandant of the U.S. Marine Corps Gen. James F. Amos, center left, listen as British Prime Minister David Cameron, right, speaks during a defense chiefs strategic dialogue with the U.S. Joint Chiefs of Staff and their British counterparts June 10, 2014, in London. (DoD photo by Mass Communication Specialist 1st Class Daniel Hinton, U.S. Navy/Released)