The request for additional forces by the U.S. commander in Afghanistan, Gen. Stanley McChrystal, poses cruel dilemmas for President Obama. If he refuses the recommendation and General McChrystal's argument that his forces are inadequate for the mission, Obama will be blamed for the dramatic consequences. If he accepts the recommendation, his opponents may come to describe it, at least in part, as Obama's war. If he compromises, he may fall between all stools—too little to make progress, too much to still controversy. And he must make the choice on the basis of assessments he cannot prove when he makes them.