This Article identifies, justifies, and explains the parameters of a largely ignored but important category of cases—what is here called “preventive adjudication.” In this category of cases, courts offer opinions without any “command” to the parties, and these opinions are meant to avoid future harm, not remedy past harm. Despite receiving little attention in the legal literature, preventive adjudication is pervasive throughout the law. It happens in declaratory judgment actions about wills, patents, and unconstitutionally vague statutes; in paternity and maternity petitions; in petitions to have missing persons declared dead; in boundary disputes; in actions to quiet title. This Article explains what preventive adjudication is and how it should and should not be used.

Preventive adjudication is intuitively appealing, because it helps people avoid harm and clarifies the law. But there are downsides to deciding cases in advance instead of waiting for remedial adjudication. The argument for preventive adjudication is therefore a qualified one. This Article identifies not only the merits of preventive adjudication but also the crucial limiting principles. One limiting principle is administrative and error costs; another is the adequacy of discounting (that is, taking into account the uncertainty of future events). People discount for many kinds of uncertainty, and discounting is usually adequate for uncertainty caused by law. But discounting is inadequate when the law causes uncertainty about inescapable threshold questions for human behavior, such as legal parenthood, citizenship, marital status, or death. Discounting is also inadequate for uncertainty about property rights because of how uncertainty undermines the rationales for having property rules in the first place (such as encouraging efficient investment and information gathering by property owners). In short, where discounting is inadequate, preventive adjudication is especially valuable.

This Article also shows how this normative understanding of preventive adjudication can be translated into the actual practice of courts in the United States. Legal systems in the United States have two ways of determining which cases should be decided by preventive adjudication: sometimes they rely on judicial discretion to decide if preventive adjudication is appropriate in each case (“retail sorting”); and sometimes they specify categories of cases in which preventive adjudication is available (“wholesale sorting”). An analysis of both approaches shows that wholesale sorting—which is common in state courts but not in federal courts—better aligns the actual practice of preventive adjudication with the cases in which it is justifiable.