War supporter Robert Kagan posits it:
If the war is going badly in the summer and fall of 2012, it will be because of the decision the president made this week. Everyone will know he did it against the advice of his commanders. Everyone will know he did it for political reasons. So if the war is going badly a year from now, whom do you think the American people will blame? There will still be 70,000 American troops in Afghanistan, but as part of a losing effort. Will Americans reward Obama at the polls under those circumstances?
Many Republicans have gone easy on Obama over his troop-exit decision. So long as they don’t outright agree with him, they have the luxury of biding their time and pouncing if things go wrong. Of course, the war may not go badly, in which case Obama will have the upper hand.