When George W. Bush campaigned for the White House, he was such a novice in foreign policy that he couldn't name the president of Pakistan and momentarily suggested he thought the Taliban was a rock-and-roll band. But he relied upon a group called the Vulcans--an inner circle of advisers with a long, shared experience in government, dating back to the Nixon, Ford, Reagan and first Bush administrations. After returning to power in 2001, the Vulcans were widely expected to restore U.S. foreign policy to what it had been under George H. W. Bush and previous Republican administrations. Instead,...