THE REPORT OF THE Iraq Study Group outlines a military strategy for Iraq that has already been embraced in large measure by the Iraqi government and U.S. military commanders, if not explicitly by President Bush. It foresees a year-long shift of U.S. forces from fighting insurgents and preventing sectarian war to advising and supporting an Iraqi army that would take responsibility for those missions. If all went well, most U.S. combat units would withdraw by early 2008, but a "robust" American force would stay on to guard against the collapse of the Iraqi government, to fight al-Qaeda and to deter intervention by Iraq's neighbors....