American Society of International Law Proceedings
What useful role (if any) could legal positivism play in the study or advancement of international law? For most of those who remember this once fashionable term at all, "international legal positivism" is redolent of the early years of the twentieth century-of Lassa Oppenheim' at best, and at worst of his model, John Austin, who famously denied that international law is or ever could be genuine law at all, "properly so called." 2 "Positive" law in its central and most usual sense is law "set by a sovereign individual or a sovereign body ... to a person or persons in a state of subjection to its author," and legal "positivism" is the doctrine that there is and can be no law but positive law. Seen in this way, international law, which rests substantially on opinio juris and "the general principles of law recognized by civilized nations," will never fit the positivist paradigm.
So why revive international legal positivism? I would suggest that despite its longstanding antipathy toward international legality and its radical failure as a general theory of law, legal positivism has always played a useful role in the progressive development of international legal institutions. Positive law has been part of international law from the beginning and will become increasingly important as international institutions become stronger. Legal positivism is a powerful tool for bringing greater clarity into international law. The better and more just the constitution of international society becomes, the more important and useful international legal positivism will be.
What Useful Role (if any) Could Legal Positivism Play in the Study or Advancement of International Law?, 106 Am. Soc'y Int'l L. Proc. 373 (2012).