Curtis Bradley and Mitu Gulati have offered (1) a carefully argued and nuanced approach to a central dilemma in international legal theory: once constituted, can customary international law ("CIL") norms ever be supplanted? As tempting as it might be to weigh-in on the intellectual and doctrinal history of what Bradley and Gulati refer to as the "Mandatory View"--that States may not unilaterally withdraw from CIL rules once such rules are formed (2)--my contribution here focuses on two, related claims made by Bradley and Gulati and their normative implications. Bradley and Gulati's first claim has to do with a crucial feature of the birth of CIL: the ability of States as persistent objectors to block the formation of custom. The second claim refutes the possibility that, once birthed, CIL cannot--under the Mandatory View--ever really die. Both these claims require further elaboration and qualification.
I. PERSISTENT OBJECTION
Bradley and Gulati's first claim is that there is an apparent disconnect in international legal theory which allows States to unilaterally opt-out of the formation of a rule as CIL, but, once "crystalized," that norm cannot be subsequently violated. This is known as the "persistent objector" rule. Bradley and Gulati ask whether the rule was really intended to be an exception to the Mandatory View and thus whether the rule has obscured the possibility that international actors have, in fact, embraced a "Default View," allowing States to opt-out of a CIL norm with sufficient notice and expectation safeguards. (3) In large measure this debate turns on the proper reading of a number of canonical decisions issued by the International Court of Justice ("ICJ") in the mid-twentieth century. (4) This was just the time (Bradley and Gulati argue (5)) that the Mandatory View was stealthily supplanting the Default View.
The first of these, The Asylum Case, (6) implicated a most peculiar custom. The case arose when a Peruvian military leader, Victor Raul Haya de la Torre, took refuge in the Colombian embassy in Lima after leading an unsuccessful coup attempt. Elsewhere in the world, this would have resulted in a very long stay for Haya de la Torre. For while all nations respect the inviolability of foreign embassy premises, there is certainly no rule requiring a host State to allow a political refugee safe passage out of the embassy, out of the country, and to the asylum State. Nowhere, that is, except Latin America, where there evolved a regional custom of diplomatic asylum.
Imagine, then, the surprise of the Colombian authorities, who, after waiting a few months, made what they assumed was a pro forma request to Peru to grant Haya de la Torre safe passage to Colombia. The Peruvians turned them down, asserting that they were not bound by the regional custom of diplomatic asylum. The Court ultimately took Peru's side in the dispute, ruling that the regional custom was not binding. (7) Once it became clear that Colombia bore the burden of showing that Peru's conduct violated international law (as opposed to Peru being required to explain its actions), the result was inevitable.
The most significant aspects of this case were the ICJ's treatment of a State's reaction as proof of its opposition to the formation of a custom and its discounting of regional custom as a source of international law. The Court ruled that where a regional (as distinct from a global) custom was concerned, silence on the part of the State in the face of an emerging practice meant that that State objected or protested to the rule. A silent or ambiguous response meant rejection. This ran counter to the general presumption in international law that States were obliged to protest loud and often if they wished to avoid being bound by a rule of emerging global custom.
Why, then, did the World Court change the calculus of consent for regional custom in the Asylum Case? …