This paper targets a nearly universal assumption in the philosophical literature: that prepunishment is unproblematic for consequentialists. Prepunishment threats do not deter, as deterrence is traditionally conceived. In fact, a pure prepunishment legal system would tend to increase the criminal disposition of the grudgingly compliant. This is a serious problem since, from many perspectives, but especially from a consequentialist one, a primary purpose of punishment is deterrence. I analyze the decision theory behind pre and postpunishments, which helps clarify both what (...) deterrence is and how it operates in consequentialist justifications of punishment. I end by sketching a road map for the future of prepunishment as artificial intelligence and other technological advances generate increasing possibilities for its use. (shrink)