Universal Treaty Law

What will international law look like in another generation? Extrapolating from current trends can be dangerous . . . but let’s give it a try. One trend that’s well under way is the creation of universal international law. In his famous 1993 article by that name, Jonathan Charney argued that global problems require the creation of international norms that bind every state. He looked to custom as shaped by multilateral forums as the way to establish those norms, and rejected treaties as the means to the end primarily because “states’ adherence to treaties rarely approaches universal participation.”

Nearly fifteen years later, though, it seems increasingly likely that many treaties will achieve universal participation, or come very close. In a world with fewer than 200 nations, any treaty with 150 or more parties is well on its way to universality. The major treaties in human rights, humanitarian law, environmental law, the law of the sea, trade, disarmament, and diplomatic relations are all above that mark, and all are still adding parties. Some, like the Montreal Protocol (191 parties), the Convention on the Rights of the Child (193), and the Geneva Conventions (194), have virtually universal participation now.

This development will have (and is already beginning to have) some interesting consequences. To achieve universality, treaties may increasingly include carrots and sticks that make it more difficult for hold-outs to hold out, and procedures that allow their regimes to evolve by adopting amendments or interpretations that bind all parties even if they receive less than universal support. (The Montreal Protocol is a model in both respects.) Article 31(3)(c) of the Vienna Convention on the Law of Treaties will become more important as a method to resolve potential conflicts between treaties.

But I think the biggest change will be (and, again, may already be beginning) with respect to customary international law. CIL has been a useful way to bind states when there’s no treaty or the treaty has less than universal membership, but after every country in the world belongs to UNCLOS, what becomes of the customary law of the sea? When every country belongs to the Geneva Conventions, what becomes of the CIL norms they reflect? In a world with virtually no obstacles to negotiation of treaties, why should customary international law persist after the remaining areas of customary law are codified? What does it do that treaty law can’t, in a world in which treaties are the favored way of making law? One might argue that CIL will still be necessary to develop new norms, especially in response to challenges that require short-term solutions, but how has CIL proved better at that than treaties? When countries can agree on how to address a problem, they can act quite quickly through treaties. (The 2001 Stockholm Convention on persistent organic pollutants, for example, already has 150 parties.) When they can’t, how can CIL help?

In a world of universal treaty law, I expect that customary law may eventually be subsumed into subsequent practice under Article 31(3)(b) of the Vienna Convention – that is, custom will become relevant not as a basis for new norms, but as a way to shape shared understandings of existing ones. International law professors will of course be sorry to see CIL go, since we often think of it as our baby, but even babies have to grow up and leave home someday – and this baby isn’t really ours anyway.

This is the last post in my two-week stint. I want to thank the OJ team for the opportunity to visit, and say that the experience has led me to appreciate even more the quality (and quantity!) of their regular contributions.