Many have blogged on this, and Obama is starting to bore me (More Cowbell!), but here's my zwei pfennig.
There is no way Obama can pin this on his predecessor. There are too many quotes from every Dem under the sun proclaiming Afghanistan as the necessary war to defend withdrawl from Iraq. We now know those statements were Pferdkaese.
My guess is that if Obama pulls out Hillary will resign as SecState to run against him again.
I think he will neither pull completely out or go all in, but will try to fight this as politically safe as possible. And there are 50,000 names on a wall in D.C. that will give testimony as to how well that will work out.