chairman of the Joint Chiefs of Staff, Marty Dempsey, who had internalized the limits of U.S. military action in the Middle East. One time he surprised me in the hallway of the West Wing by recommending that I read Rachel Maddow’s book, Drift: The Unmooring of American Military Power. Up to this point, he had argued that Syria was a slippery slope where there was little chance of success; now he said that something needed to be done even if we didn’t know what would happen after we took action.

