From Real Clear Politics: "The political end game on Iraq"
But military odds and political odds are not one and the same, the latter being dependent on an independent, highly unpredictable variable known as the American public. Should we lose in Iraq, the odds are Republicans will take the blame. Unless, of course, the public believes that Democratic actions helped lead to that defeat. Hence, Pelosi's and Reid's differing plans that place complete withdrawal well into 2008 - in other words, well past the time they think the public could blame them for encouraging defeat.Which is why Pelosi and Reid silently cringe when they see stories like this: "Iraqi Spokesman Says Leader of Major Al-Qaeda-Linked Group Captured Near Baghdad."
But if the surge should succeed, then Democrats have a problem. Success in Iraq switches the dynamics of the gamble from avoiding blame to getting credit. And although Democrats have probably gone out on the ledge as far as they think is wise, they are still out there and vulnerable if Iraq takes a turn for the better.