Larison has Romney's number:
One advantage that Romney’s perpetual position-switching used to give him was that it created the impression that Romney was very pliable and would not persist stubbornly in a position out of deep-seated conviction or arrogance. The argument went something like this: however untrustworthy Romney seemed, and no matter how much he would pander to every audience to win votes, he would never be as willfully blind to reality as Bush was. Since the beginning of the health care debate, Romney has started to combine the worst traits of his previous presidential campaign and that stubborn obliviousness that defined Bush: he cannot let go of the Massachusetts health care bill, he cannot really acknowledge the mistakes that he helped to make, and yet he wants to make himself the standard-bearer of the opposition to the very same kind of thing he supported just a few years ago and still will not repudiate.