We propose a model where the probability that courts will enforce a statute is endogenous to the statute itself. We obtain, …rst, that the enactment of legislation prohibiting something might raise the probability that courts will allow related things not expressly forbidden. We call that a 'permitting prohibition'and discuss examples that are consistent with the model. Second, we obtain that dispersion of court decisions might be greater with legislation that commands little court deference, than with legislation that commands none. Thus, within a certain range, legislation improvement might trade-o¤ with court predictability.