Most economic and positive political theory presumes the existence of an effective legal regime (protecting property rights or implementing legislative or judicial choices, for example). Yet social science has devoted little systematic attention to the question of what constitutes distinctively legal order. Most social scientists take for granted that law is defined by the presence of a centralized authority capable of exacting coercive penalties for violations of legal rules. Moreover, the existing approach to analyzing law in economics and positive political theory works with a very thin concept of law, one that does not account for the distinctive attributes of legal order as compared with other forms of social order. This approach, however, leaves us with few tools to answer key questions about the emergence and maintenance of legal order, particularly in settings with weak governance. In this paper we discuss three of the key case studies that appear in the law, economics and politics literature and which explore the role of “law” in securing social order: medieval Iceland, California during the gold rush and the world of the medieval merchants in Europe and the Muslim Mediterranean. Drawing on a model we have developed elsewhere (Hadfield and Weingast 2012), we reinterpret these case studies to demonstrate how a theoretically-informed approach to law, one that employs a rich conception of what is distinctive about law and which, in particular, attends to the problems of coordinating decentralized collective punishment, illuminates key questions about the emergence, stability and function of law in supporting economic and democratic growth.