IS CUSTOMARY INTERNATIONAL LAW REALLY LAW?

One of the most fundamental conceptual enigmas of customary international law is whether it really counts as law at all. Legal philosophers have, of course, long debated the meaning of law and whether international law in fact satisfies a given definition of “law,” particularly because of the current absence of any centrally regulated regime of enforcement. Customary international law is particularly susceptible to doubts about its character as law.

Many political scientists have viewed customary norms as mere “regimes” based on political self-interest, treating them simply as pragmatic conventions that states usually follow but that they are under no obligation to obey. This view has been echoed by some legal scholars who are deeply skeptical that customary international law exercises any “exogenous influence on state behavior.”

Even legal philosophers have had similar doubts about whether customary law norms qualify as “law” or as part of a “legal system.” For example, although H.L.A. Hart described some similarities between international law and municipal law and acknowledged that particular customary rules existed, he concluded that international rules did not yet represent a full-fledged legal system because of the absence of a general “rule of recognition” regarding the validity of international law norms. Indeed, he believed that the norm that “States should behave as they have customarily behaved” – the foundation of customary international law – was not a basic rule of recognition.