The Customary International Law Supergame February 23, 2004 is no overarching state, per se. So, in the international system, there is more overlap, and an indistinct border, between law and social norms. This overlap is perhaps easier to see in the international context than in the domestic context as in the international context, a significant subset of social norms is termed law. Ellickson states that the social norms literature defines a" social norm as"a rule governing an individuals behavior that third parties other than state agents diffusely enforce by means of social sanctions. "l9 The focus of this definition on decentralized means of enforcement shows the strong analogy between social norms in the municipal setting and cil in the international setting. Of course, to the extent that courts may apply, and institutions of global governance may enforce, CIL, there is a difference. But this application and enforceability is quite limited. There are few circumstances in which at the international level although action by domestic courts would certainl ageny s, O consider application of Cil by domestic courts to amount to the action of"stae ould CIL rules benefit from mandatory adjudication in international tribunals. We would not considered action of state agents"at the municipal level. This is because in the nternational context, domestic courts are simply internal deliberative processes of national governments. The application by domestic courts of cil may be understood as a kind of norm internalization. 20 One important set of explanations of social norms understands norms as preferences that individuals(or in our case states) acquire through education acculturation or other processes, such as an expressive or articulation function. Elster states that" social norms provide an important kind of motivation for action that is irreducible to rationality or indeed to any other form of optimizing mechanism We add this qualification, because one might argue that the cil and conventional law framework, as it exists, is at least comparable to a municipal state, or at least that this framework is comparable to the constitution that a municipal state might have. Of course, while it responds to some of the same questions, including a rule of recognition, it is not as detailed or fertile as a constitution Robert Ellickson, The Evolution of social Norms: A Perspective from the legal Academy, in SoCIAL NORMS 35(Michael Hechter Karl-Dieter Opp eds, 2001). Note that Ellickson assumes multilateral, as opposed to bilateral, retaliation 20 See Harold Hongju Koh, Why Do Nations Obey International Law?, 106YALELJ 2599(1997)(reviewing Abram Chayes Antonia Handler Chayes, THE NEW SOVEREIGNTY: COMPLIANCE WITH INTERNATIONAL REGULATORY AGREEMENTS (1995)) This internalization may be desirable under certain circumstances, and may be developed as a tool of enforcement of CIL. That is, states may persuade one another to harness their domestic legal system for certain of their international legal obligations, effectively holding the domestic legal system hostage. See also Philip moremen Joel P Trachtman, Whose Right is it Anyway? Private Parties in EC-US. Dispute Settlement at the WTo, 44 HARV. INT'L L J. 221(2003). See robert d. Cooter, Expressive Law and Economics, 27J LEG. STUDS. 585(1998). JON ELSTER, THE CEMENT OF SOCIETY 15(1989)The Customary International Law Supergame February 23, 2004 7 is no overarching state, per se. 18 So, in the international system, there is more overlap, and an indistinct border, between law and social norms. This overlap is perhaps easier to see in the international context than in the domestic context, as, in the international context, a significant subset of social norms is termed "law." Ellickson states that the social norms literature defines a “social norm” as “a rule governing an individual’s behavior that third parties other than state agents diffusely enforce by means of social sanctions.” 19 The focus of this definition on decentralized means of enforcement shows the strong analogy between social norms in the municipal setting and CIL in the international setting. Of course, to the extent that courts may apply, and institutions of global governance may enforce, CIL, there is a difference. But this application and enforceability is quite limited. There are few circumstances in which CIL rules benefit from mandatory adjudication in international tribunals. We would not consider application of CIL by domestic courts to amount to the action of “state agents” at the international level, although action by domestic courts would certainly be considered action of “state agents” at the municipal level. This is because in the international context, domestic courts are simply internal deliberative processes of national governments. The application by domestic courts of CIL may be understood as a kind of norm internalization. 20 One important set of explanations of social norms understands norms as preferences that individuals (or in our case states) acquire through education, acculturation or other processes, such as an expressive or articulation function. 21 Elster states that “social norms provide an important kind of motivation for action that is irreducible to rationality or indeed to any other form of optimizing mechanism . . . .” 22 It 18 We add this qualification, because one might argue that the CIL and conventional law framework, as it exists, is at least comparable to a municipal state, or at least that this framework is comparable to the constitution that a municipal state might have. Of course, while it responds to some of the same questions, including a rule of recognition, it is not as detailed or fertile as a constitution. 19 Robert Ellickson, The Evolution of Social Norms: A Perspective from the Legal Academy, in SOCIAL NORMS 35 (Michael Hechter & Karl-Dieter Opp eds., 2001). Note that Ellickson assumes multilateral, as opposed to bilateral, retaliation. 20 See Harold Hongju Koh, Why Do Nations Obey International Law?, 106 YALE L.J. 2599 (1997) (reviewing Abram Chayes & Antonia Handler Chayes, THE NEW SOVEREIGNTY: COMPLIANCE WITH INTERNATIONAL REGULATORY AGREEMENTS (1995)). This internalization may be desirable under certain circumstances, and may be developed as a tool of enforcement of CIL. That is, states may persuade one another to harness their domestic legal system for certain of their international legal obligations, effectively holding the domestic legal system hostage. See also Philip Moremen & Joel P. Trachtman, Whose Right is it Anyway? Private Parties in EC-U.S. Dispute Settlement at the WTO, 44 HARV. INT’L L. J. 221 (2003). 21 See Robert D. Cooter, Expressive Law and Economics, 27 J. LEG. STUDS. 585 (1998). 22 JON ELSTER, THE CEMENT OF SOCIETY 15 (1989)