Contingent judicial deference: theory and application to usury laws

Legislation is less likely to be enforced when courts disagree with it. Building on this premise, we propose a model of Bayesian adjudicators that use their own prior knowledge to evaluate the appropriateness of legislation. The model yields a non-monotonic relation between written rules and effectively enforced rules. Hence the enactment of legislation prohibiting something raises the probability that courts will allow related things not expressly forbidden. Moreover, legal uncertainty is greater with legislation that commands little deference from courts than with legislation that commands none. We discuss examples of effects of legislated prohibitions (and, in particular, usury laws) that are consistent with the model.