Notable American jurists and scholars have advanced an approach to contract enforcement that would render breach legally and morally uncontestable, assuming compensation follows. Much of the justification for this endeavor has rested upon claims of judicial and economic efficiency. But efficiency neither favors nor disfavors this conception of contract, formalized by the efficient breach hypothesis. This Essay develops an alternative approach to contract enforcement, expressed as the efficient performance hypothesis. The alternative approach predicts the same efficiency as the traditional one, but differs starkly in terms of its ethical understanding of contractual obligation. The efficient breach hypothesis supposes that the promisor has t...