Major US-Israel differences surfaced suddenly Thursday, Dec. 1, over the timing and circumstances of an attack on Iran's nuclear facilities, when Gen. Martin Dempsey, Chairman of the Joint US Chiefs of Staff, said: "I don't know whether Israel would alert the United States ahead of time if it decided to take military action against Iran." Three hours later, Israeli Defense Minister Ehud Barak maintained US policy would enable Iran to obtain a nuclear weapon without the possibility of attacking it.