This article presents a critical reevaluation of the thesis—closely associated with H. L. A. Hart, and central to the views of most recent legal philosophers—that the idea of state coercion is not logically essential to the definition of law. The author argues that even laws governing contracts must ultimately be understood as “commands of the sovereign, backed by force.” This follows in part from recognition that the “sovereign,” defined rigorously, at the highest level of abstraction, is that person or entity (...) identified by reference to game theory and the philosophical idea of “convention” as the source of signals with which the subject population has become effectively locked, as a group, into conformity. (shrink)