In the mid-nineteenth century, the great anthropologist Henry Sumner Maine observed that legal systems tended to move over time from “status to contract” by which he meant that rights and duties were increasingly determined by consent rather than social or demographic factors. Maine’s thesis might have been applied to international law during the long era of high positivism, in which consent became the dominant principle after the Peace of Westphalia. Formal equality of states meant that formal treaties—”contract”—were the main mode of interaction. Even in the post-World War II era, consent played a major role, in part because the Security Council—the chief vehicle for legal exercise of “status”—was anemic. International organizations served as vehicles for the development of multilateral treaties of increasing scope and depth. Status and power were hidden rather than acknowledged elements of the system.