Secretary of Defense Ash Carter,center, testifies before the Senate Armed Services Committee on behalf of the Iranian nuclear deal recently brokered by the Obama administration in Washington, July 29, 2015. Carter was joined by Secretary of State John Kerry, from left, U.S. Treasury Secretary Jack Lew, Energy Secretary Ernest Moniz and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey. (DoD Photo by Glenn Fawcett /Released)