the way it is painted in the interview, the scene is vary bleak. the first option is to try to make things better while staying in there, fighting an up-hill battle and the other option is stand back and let this frail state of affairs collapse and reconstruct it with a stable foundation. the former option will take a heavy toll on the american force in the region but that will be the brunt of the casualties (all things associated). the second option includes a significantly larger amount of bloodshed among the sunni population and to a lesser degree, also the shiites.
i foresee the blame panning out like this. if the amercians leave asap and all hell breaks loose it will be seen as they came in, threw order (for what its worth) out the window and left the region when they lost their appetite, making american forign policy look vary much less conducive to world peace then before the war. if they stay in there and somehow manage to stabilize the region before they leave, the american people will insist it was not the place of the usa to take the burdens of the region, whereas the rest of the world will consider the action noble although misguided. however, if the american force stays there for a few more years then decides to leave without stability after all, the american people will be even more upset and the rest of the world will think they screwed up in every way and are not only vary unpeacefull but also incompetent.
all 3 of these scenarios are considering no WMDs turn up. if they do turn up, there will be many big investigation into weather they were really found or if they are someone else's WMDs, if they are still the real deal then everyone will appologize for ever doubting and let's not play the blame game and let's move on.
the only way to win is to stay in and pull off a miracle