James Baker of the Iraq Study Group is Bush I's go-to guy when W gets in real trouble (as in Florida 2000).
I imagine he sees his mandate as preserving the Bush legacy. That being the case, we now have Rumsfeld as the absent scapegoat for the current situation. Baker & the ISG will come up with a plan (doesn't matter what the plan is); Congress will be quick to endorse it, because otherwise they'd have to come up with their own plan, which would entail responsibility for its efficacy (something they *really* don't want).
Bush then will be able to say that the ISG & Congress have shown him the only politically practical way forward, and if that plan then fails, it won't be his fault, it will be the fault of the ISG & Congress. I'm sure W and his handlers already blame the electorate for being too weak-minded to support his proper plan of staying the course.
Does that secure the Bush legacy? Does it harm the newly-Democrat controlled Congress, or are they protected in the same way as Bush (i.e., if the plan fails, it's the ISG's fault)?