The Customary International Law Supergame February 23, 200 well. Since the publication by Robert Ellickson of Order Without Law in 1991, legal scholars have examined the role of informal norms in society, and the relationship of these norms to law. Ellickson investigates how cattle farmers in Shasta County California, manage to establish and apply their own non-legal rules, with a notable level of compliance, without direct intervention by the state. It is an insightful story about how order can arise without law, or in spite of law We may draw a rough, and limited, analogy between the development of social norms in a municipal, or private setting, and the development of CIl in the international public setting. In the international community, CiL is substantively similar to the phenomenon Ellickson describes. In international political science, regime theorists uch as robert Keohane, Stephen Krasner, and Beth Simmons have told a similar story of the possible rise of order in international society. However, regime theory has generally avoided cIL. Moreover, recognition that a rule has become part of CIl may signal its support by, or linkage with, the multi-Sector CIL system. This system of accepted and enforced linkage may distinguish legal rules from non-legal regimes he difference between law and social norms in the municipal setting is that law is the province of the state(setting aside for the moment religious law, other non-state rules, and circumstances in which non-state made rules are incorporated in the state- enforced law). However, this distinction is inapposite to the international system, which has been characterized as a horizontal, as opposed to vertical, system, where there ROBERT ELLICKSON, ORDER WITHOUT LAW(1991) I However, one might argue that the general legal system, including especially its rules against violence, forms an important background or infrastructure that may provide upport to the farmers' social norms For a recent work synthesizing and extending some of the social norms learning, see ERIC A POSNER, LAW AND SOCIAL NORMS(2000). See also richard H. McAdams, Book Review: Signaling Discount Rates: Law, Norms and Economic Methodology, 110 YALE LJ.625(2001). For an example of this type of analogical allegory, comparing domestic custom to international custom, see Mendelson, supra note 8, at 165-168. For an early statement that CiL is produced in an evolutionary fashion, see ANTHONY A D'AMATO, THE CONCEPT OF CUSTOM IN INTERNATIONAL LAW 104(Cornell 1971) See, e.g., ROBERT O. KEOHANE, AFTER HEGEMONY: COOPERATION AND DISCORDIN THE WORLD POLITICAL ECONOMY(1984); ROBERT O KEOHANE, INTERNATIONAL INSTITUTIONS AND STATE POWER: ESSAY IN INTERNATIONAL RELATIONS THEORY(1989) See, e.g, STEPHEN D. KRASNER, INTERNATIONAL REGIMES (1983); Stephen Krasner Beth Simmons, Theories of International Regimes, 41 INT'L ORG. 491(1987) 16 Duncan Nidal, Political Economy and International InstitutionS, 16 INT'L REV. L.& ECON.121,124(1996) ile there is no state at the global level, there is an international legal and organizational order, which is quite a bit more fragmented than most nation-statesThe Customary International Law Supergame February 23, 2004 6 well. Since the publication by Robert Ellickson of Order Without Law 10 in 1991, legal scholars have examined the role of informal norms in society, and the relationship of these norms to law. Ellickson investigates how cattle farmers in Shasta County, California, manage to establish and apply their own non-legal rules, with a notable level of compliance, without direct intervention by the state. It is an insightful story about how order can arise without law, or in spite of law. 11 We may draw a rough, and limited, analogy between the development of social norms in a municipal, or private setting, 12 and the development of CIL in the international public setting. In the international community, CIL is substantively similar to the phenomenon Ellickson describes. 13 In international political science, regime theorists such as Robert Keohane, 14 Stephen Krasner, and Beth Simmons 15 have told a similar story of the possible rise of order in international society. However, regime theory has generally avoided CIL. 16 Moreover, recognition that a rule has become part of CIL may signal its support by, or linkage with, the multi-sector CIL system. This system of accepted and enforced linkage may distinguish legal rules from non-legal regimes. The difference between law and social norms in the municipal setting is that law is the province of the state (setting aside for the moment religious law, other non-state rules, and circumstances in which non-state made rules are incorporated in the state￾enforced law). 17 However, this distinction is inapposite to the international system, which has been characterized as a horizontal, as opposed to vertical, system, where there 10 ROBERT ELLICKSON, ORDER WITHOUT LAW (1991). 11 However, one might argue that the general legal system, including especially its rules against violence, forms an important background or infrastructure that may provide support to the farmers' social norms. 12 For a recent work synthesizing and extending some of the social norms learning, see ERIC A. POSNER, LAW AND SOCIAL NORMS (2000). See also Richard H. McAdams, Book Review: Signaling Discount Rates: Law, Norms and Economic Methodology, 110 YALE L.J. 625 (2001). 13 For an example of this type of analogical allegory, comparing domestic custom to international custom, see Mendelson, supra note 8, at 165-168. For an early statement that CIL is produced in an evolutionary fashion, see ANTHONY A. D'AMATO, THE CONCEPT OF CUSTOM IN INTERNATIONAL LAW 104 (Cornell 1971). 14 See, e.g., ROBERT O. KEOHANE, AFTER HEGEMONY: COOPERATION AND DISCORD IN THE WORLD POLITICAL ECONOMY (1984); ROBERT O. KEOHANE, INTERNATIONAL INSTITUTIONS AND STATE POWER: ESSAY IN INTERNATIONAL RELATIONS THEORY (1989). 15 See, e.g., STEPHEN D. KRASNER, INTERNATIONAL REGIMES (1983); Stephen D. Krasner & Beth Simmons, Theories of International Regimes, 41 INT’L ORG. 491 (1987). 16 Duncan Snidal, Political Economy and International Institutions, 16 INT'L REV. L. & ECON. 121, 124 (1996). 17 While there is no state at the global level, there is an international legal and organizational order, which is quite a bit more fragmented than most nation-states