Symposium: Discussion of Kontorovich’s “Inefficient Customs in International Law”

[Andrew Guzman is Professor of Law at UC Berkeley, Boalt Hall and a discussant in the Opinio Juris On-line Symposium. He blogs regularly at the International Economic Law and Policy Blog]



Eugene Kontorovich’s paper, Inefficient Customs in International Law is a welcome contribution to the growing analytical literature on customary international law (CIL). The question asked here is of obvious importance: are rules of CIL likely to be efficient? If the rules are efficient they improve overall welfare (however measured) and if not they reduce it. There remains a question of how the conclusion that international law rules (such as those governing the formation of CIL) affect outcomes given that there is no institution capable of changing those basic rules. This is an awkward question here, but it is similarly awkward with respect to a great deal of international law scholarship that includes a normative component.



Rather than attempting to determine if CIL in its entirety yields some form of net efficiency gain, Eugene remains agnostic about the desirability of CIL as a single general category. The key thrust of the article is a call to evaluate individual instances of CIL in an attempt to determine if they are likely to be efficient. This evaluation is to be done using a multifactor test that includes the number of states involved, the extent to which relevant transactions are repeated over time, the homogeneity of the group, the presence of reciprocity, and whether the rules govern insiders only or also affects outsiders. As with any multifactor test application here is a challenge. There is no metric to evaluate any one of these categories (e.g., how many states count a “a lot?” Ten? Twenty? Fifty? Two hundred?) and no way to know how much weight should be given to each. This difficulty is apparent when Eugene attempts to apply the criteria to specific categories of CIL (diplomatic relations, war, and human rights). The analysis is necessarily ad hoc and one wonders if there is any way to separate the multi-factor test from a direct and subjective assessment of whether the substantive rule seems efficient or not. That may not be so bad, however, as this sort of direct assessment may be a good way to evaluate the efficiency of CIL rules.



Eugene proposes that CIL rules be subjected to “structural adjudication,” a process in which customs would “only be given legal status when they arose in an environment conducive to the production of efficient norms.” Whatever else one thinks of this proposal, it can only apply to that very narrow slice of CIL that comes to be adjudicated before an international tribunal (it could be done before a domestic tribunal, but the question of bias in such a context would outweigh the gains from the structural analysis the Eugene calls for). It would be helpful to consider the bulk of CIL norms – those that do not get adjudicated – could be evaluated.



Something else should be said about comparing the doctrine of CIL to some notion of efficiency. As is clear to anyone observing CIL (and as Eugene clearly recognizes) some rules of CIL exist despite the fact that the supposed requirements of opinio juris and general practice are absent. CIL rules of human rights are the most conspicuous of these. Whatever makes a CIL rule against torture exist, it is not the combination of opinio juris and general practice. Because Eugene’s project asks whether CIL rules that arise under the standard doctrinal test are efficient, his analysis does not speak as directly to the efficiency of human rights norms that arise in some other way. This does not undermine the claims Eugene makes, but it narrows them. To be fair to Eugene, whatever process leads to the adoption of rules of CIL outside of the classic definition is quite likely to be an even less efficient process.



I have tried to raise a couple questions about the discussion in this paper, but the bottom line is that this is a good and valuable paper. There are aspects of it that could be contested, but the question, method, and analysis strikes me as basically right. Academic papers are worthwhile if they affect the way we think about significant questions, and Eugene’s paper on the efficiency of CIL does exactly this.