The notion that a court tasked with enforcing a private agreement should be allowed – even, in some cases, required – to withhold enforcement because of the unfairness of the agreement is not a new one; scholars have traced it back well beyond the earliest days of the Anglo-American legal system. In the United States, the current formulation of that idea can be found principally in the doctrine of unconscionability, which has enjoyed since its incorporation into the Uniform Commercial Code a place in the menu of contract law’s policing doctrines, even if a somewhat insecure and sometimes disputed one.

The chapter summarizes with a few broad strokes the earlier story of modern unconscionability law in the United States. This chapter will then focus on the history of that doctrine in American courts over the last two decades, identifying those situations in which it has been most frequently advanced, and those where it has been most likely to succeed. This also entails exploring the interaction of that doctrine with the federal law favoring the enforcement of private contractual agreements to submit future disputes to arbitration. Finally, the chapter considers the possible future development of unconscionability law, with particular regard to the continued utility of the “procedural-substantive” dichotomy, and the employment of unconscionability as a tool for policing contracts of adhesion.