Witnesses testifying before the Senate Armed Services Committee on Capitol Hill in Washington, Wednesday, April 14, 2010, about U.S. policy toward Iran's nuclear program are, from left to right: Undersecretary of Defense for Policy Michele Flournoy, Undersecretary of State for Political Affairs William Burns, Marine General James Cartwright, the vice chairman of the Joint Chiefs of Staff, and Lt. Gen. Ronald Burgess, head of the Defense Intelligence Agency. (AP Photo/J. Scott Applewhite)