The compatibility of determinism and the ability to do otherwise has been implicitly assumed by many to be irrelevant to the viability of compatibilist responses to the manipulation argument for incompatibilism. I argue that this assumption is mistaken. The manipulation argument may be unsound. But even so, the manipulation argument, at the very least, undermines classical compatibilism, the view that free will requires the ability to do otherwise, and having that ability is compatible with determinism. This is because classical compatibilism, (...) in conjunction with any type of reply to the manipulation argument, has counterintuitive implications. In order to avoid such implications, we need not hold that determinism is incompatible with moral responsibility. But we must hold that determinism is incompatible with the ability to do otherwise. (shrink)