Punishing someone for a crime before they have committed it is widely considered morally abhorrent. But there is little agreement on what exactly is supposed to be wrong with it. In this paper, I critically evaluate several objections to the permissibility of prepunishment, making points along the way about the connections between time, knowledge, desert, deterrence and duty. I conclude that, although the conditions under which it could permissibly be administered are unlikely ever to arise in practice, nevertheless in principle, (...) nothing is wrong with prepunishment after all. (shrink)