Prosper Weil's article in the American Journal of International Law first appeared in 1982 in French in the Revue Générale de Droit International Public. In France, it has probably generated less debate than in the United States. Indeed, the positions taken by this stimulating, agile, and well-written article generally accord with the doctrinal tradition that largely predominates in the land of Jean Bodin, René Descartes, and Auguste Comte, namely, legal positivism. According to this tradition, legal scholars must first focus on the technical analysis of legal norms as they are set out and, above all, practiced by the various actors in legal relations, which on the international level are states and the international judge or arbitrator. After setting out the contexts of Weil's article, I shall state two reservations to its content and then turn to its contemporary relevance.

By all rights, Prosper Weil's 1983 cri de coeur should be one of many best-forgotten law review articles. It targets, after all, concepts that few dispute today (namely jus cogens and erga omnes obligations, as well as shortcuts to finding universally applicable customary law based on “quasi-universal” treaties). Its other direct target—the distinction between international crimes and delicts—refers to once contentious debates over whether states can be charged with ordinary international delicts as well as international crimes. This has since been eclipsed by the International Law Commission's (ILC's) decision to include, in its Articles of State Responsibility, Article 41 (enumerating the consequences of “serious breaches” resulting from the violation of preemptory norms). And insofar as Weil's foil was the premise that international “delicts” can have a “variable geometry,” that too has been overtaken by events: neither the ILC's turn to “serious breaches” nor the far older proposition that individuals can be prosecuted for international crimes remains the subject of much controversy today.

Nowadays, Prosper Weil's concerns about the emergence of international rules protecting so-called community values, and thus being endowed with special normative force in comparison to “ordinary” international rules, cannot but appear excessive. The existence of such rules as jus cogens or as rules establishing erga omnes obligations is undisputed. And yet Prosper Weil's prediction of their negative impact on the essential functions of international law has not materialized. Weil's concerns acquire instead significance in the field of international criminal law, whose development in the last decades is premised on the need to protect values fundamental to the international community as a whole through the threat of a criminal sanction against individual transgressors.

This essay focuses on the understanding of positivism in Prosper Weil's time, its trajectory since, and how that trajectory reflects changes that have occurred in global society in the intervening years. The world to which Weil spoke is neither in scientific nor in political and cultural terms the same as ours. Key positivist notions, such as neutrality or Weil's critique of the ideal of the unity of the international community and of the invocation of higher moral values, appear to chain sound normative principles while letting loose real power. At any rate, Weil's ideas have not survived globalization or the critical and historical turn taken in the discipline of international law. And yet “Towards Relative Normativity?” arguably owes its lasting significance to its grasp of the weight of the authority of law in international society.

Prosper Weil's scintillating intervention of 1983 warned against pathological doctrinal tendencies that threatened to “disable international law from fulfilling what have always been its proper functions.” Weil concluded his sweeping critique of these supposed pathologies with an urgent call for remedial action: “[A]ll is not yet lost . . . . There is still time for jurists to react.” But, as José Alvarez points out in his contribution to this symposium, the manifestations of “relative normativity” that Weil decried—such as the doctrine of jus cogens and the transmutation of customary law into universal law—have only entrenched themselves more firmly in the decades since his famous article was published. So, what is the point of engaging with “Towards Relative Normativity in International Law?” today beyond its historical significance as a celebrated, but ultimately failed, rallying cry against the doctrinal revolution that has swept over international law in the period since decolonization?

Prosper Weil misfired his volleys by targeting his protestations at relative normativity in international law. In itself, relative normativity is unavoidable and beneficial. The enduring value of his celebrated 1983 article “Towards Relative Normativity in International Law?” lies in identifying the various problems that he associated with relative normativity. These problems deserve serious attention and conscientious responses in order to assure the health of the international legal system as well as the international community. The idea of an international law of co-progressiveness that I have developed, though not intended as a direct response to these problems, does come with a toolkit full of responses that would go a long way to solving those problems or at least reducing them to a minimum.