Defense Secretary Ash Carter said Wednesday that the U.S. armed forces stand ready to confront Iran, but told lawmakers that a successful implementation of the nuclear agreement with Tehran is preferable to a military strike. Carter, Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, and three members of President Barack Obama's Cabinet testified at a committee hearing as part of the White House's aggressive campaign to convince Congress to back the Iranian nuclear deal, which calls on Iran to curb its nuclear program in exchange for billions of dollars in sanctions relief.