¹ See, e.g., Ian Buruma, The End of the Anglo-American Order, N.Y. Times Mag. (Nov. 29, 2016), at https://www.nytimes.com/2016/11/29/magazine/the-end-of-the-anglo-american-order.html; see generally G. John Ikenberry, The End of Liberal International Order?, 94 Int'l Aff. 7 (2018) (discussing these trends).

² See William Magnuson, Is Brexit the Beginning of the End for International Cooperation?, Conversation (Mar. 30, 2017), at http://theconversation.com/is-brexit-the-beginning-of-the-end-for-international-cooperation-70865.

³ See Peter Baker, Trump Abandons Trans-Pacific Partnership, Obama's Signature Trade Deal, N.Y. Times (Jan. 23, 2017), at https://www.nytimes.com/2017/01/23/us/politics/tpp-trump-trade-nafta.html.

⁴ See Galbraith, Jean, Contemporary Practice of the United States, 112 AJIL 745 (2018)Google Scholar (discussing the United States’ withdrawal from the UN Human Rights Council); Daugirdas, Kristina & Mortenson, Julian Davis, Contemporary Practice of the United States, 111 AJIL 1036 (2017)Google Scholar [hereinafter Paris Agreement] (discussing the United States’ plans to withdraw from the Paris Agreement).

⁵ See Brewster, Rachel, The Trump Administration and the Future of the WTO, 44 Yale J. Int'l L. Online 6 (2018)Google Scholar (discussing these aspects of “the Trump Administration's strategy to undermine the WTO”); Shaffer, Gregory, A Tragedy in the Making? The Decline of Law and the Return of Power in International Trade Relations, 44 Yale J. Int'l Law Online 37 (2018)Google Scholar (observing that the Trump administration's attacks against the WTO could result in “a long-term decline of multilateralism” in international trade law).

⁶ See Soley, Ximena & Steininger, Silvia, Parting Ways or Lashing Back? Withdrawals, Backlash, and the Inter-American Court of Human Rights, 14 Int'l J. L. in Context 237 (2018)CrossRefGoogle Scholar (discussing the Dominican Republic, Peru, Trinidad and Tobago, and Venezuela); see generally Laurence R. Helfer, Populism and International Human Rights Institutions: A Survivor's Guide (iCourts Working Paper Series No. 133, 2018) (analyzing these and other populist challenges to the international human rights system).

⁷ See Philipe Villamor, Philippines Plans to Withdraw from International Criminal Court, N.Y. Times (Mar. 14, 2018), at https://www.nytimes.com/2018/03/14/world/asia/rodrigo-duterte-philippines-icc.html; Ssenyonjo, Manisuli, State Withdrawal Notifications from the Rome Statute of the International Criminal Court: South Africa, Burundi and The Gambia, 29 Crim. L. Forum 63 (2018)CrossRefGoogle Scholar.

⁸ Some observers characterize the current backlash against multilateral norms and institutions as a natural course correction. See, e.g., Cohen, Harlan Grant, Multilateralism's Life-Cycle, 112 AJIL 47 (2018)CrossRefGoogle Scholar. Others consider recent events to be merely the inevitable growing pains of regulatory globalization—a brief setback in multilateralism's indomitable forward march. See, e.g., Gary Pinkus, James Manyika & Sree Ramaswamy, We Can't Undo Globalization, But We Can Improve It, Harv. Bus. Rev. (Jan. 10, 2017), at https://hbr.org/2017/01/we-cant-undo-globalization-but-we-can-improve-it. We prescind from commenting on the causes and likely duration of the backlash. For our purposes, the populist backlash against international institutions is sufficient to underscore the importance of apprehending the nature of multilateralism and its international legal obligations.

⁹ See, e.g., Ryan Goodman & Derek Jinks, Socializing States: Promoting Human Rights Through International Law (2013); Robert O. Keohane, After Hegemony: Cooperation and Discord in the World Political Economy (1984); Shanks, Cheryl, Jacobson, Harold K. & Kaplan, Jeffrey H., Inertia and Change in the Constellation of International Governmental Organizations, 1981–1992, 50 Int'l Org. 593 (1996)CrossRefGoogle Scholar.

¹⁰ We discuss voluntarism in Part III. Notable critiques of voluntarism include Hersch Lauterpacht, Private Law Sources and Analogies of International Law 43–71 (1927); J.L. Brierly, The Basis of Obligation in International Law and Other Papers 144 (1958); Antônio Augusto Cançado Trindade, International Law for Humankind: Toward a New Jus Gentium 16–20 (2010).

¹¹ Legal scholars have, however, considered the extent to which international obligations can be imposed without state consent. See, e.g., Krisch, Nico, The Decay of Consent: International Law in an Age of Global Public Goods, 108 AJIL 1 (2014)Google Scholar; Guzman, Andrew T., Against Consent, 52 Va. J. Int'l L. 747 (2012)Google Scholar; Helfer, Laurence R., Nonconsensual International Lawmaking, 2008 U. Ill. L. Rev. 71 (2008)Google Scholar. This Article's focus is conceptual and normative rather than empirical, and therefore does not address the extent to which states comply with mandatory multilateralism. Nonetheless, we hope the arguments developed here will inspire empirical work in this area.

¹² Cf. Ruggie, John Gerard, Multilateralism: The Anatomy of an Institution, 46 Int'l Org. 561, 565–66 (1992)CrossRefGoogle Scholar (distinguishing “nominal” from “qualitative” multilateralism, but offering different definitions for each).

¹³ See, e.g., Simma, Bruno, From Bilateralism to Community Interests in International Law, 250 Recueil des Cours 217 (1994)Google Scholar.

¹⁴ For a discussion of the spectrum of multilateral cooperation, see Patrick, Stewart M., The New “New Multilateralism”: Minilateral Cooperation, but at What Cost?, 1 Glob. Summitry 115 (2015)CrossRefGoogle Scholar. By “omnilateralism” we mean multilateralism in which all states either participate in lawmaking or are entitled to become parties to international agreements of potentially universal scope.

¹⁵ We will have more to say about the substantive and procedural requirements associated with “due regard” in Part IV.

¹⁶ We reserve for another day consideration of the question whether, or to what extent, international law requires states to cooperate with non-state actors, and vice versa.

¹⁷ We discuss a number of these settings in Part II.

¹⁸ Joint stewardship refers to collective state governance of multilateral regulatory regimes established by international law over matters of transnational and sometimes global concern, such as the deep sea floor or endangered species. We discuss joint stewardship infra, at Part III.

¹⁹ By “the parties and legal institutions” we mean to refer to states that are bound by international norms through treaty or custom, as well as international tribunals that have jurisdiction to adjudicate disputes concerning the application of those norms. The point of this qualification, however, is to take up an internal point of view regarding international law, not to deny the obvious fact that litigants are bound to disagree on the meaning and applicability of the norms purported to govern their dispute.

²⁰ For an introduction to the scope and stakes of this dispute, see Council on Foreign Relations, Territorial Disputes in the South China Sea, at https://www.cfr.org/interactives/global-conflict-tracker#!/conflict/territorial-disputes-in-the-south-china-sea.

²¹ See Daugirdas & Mortenson, Paris Agreement, supra note 4.

²² See generally Obligation to Negotiate Access to the Pacific Ocean (Bol. v. Chile) (Int'l Ct. Just.), at http://www.icj-cij.org/en/case/153.

²³ UN Framework Convention on Climate Change, pmbl., May 9, 1992, 1771 UNTS 107 (entered into force Mar. 21, 1994), available at http://unfccc.int/resource/docs/convkp/conveng.pdf [hereinafter UNFCCC].

²⁴ See UN Convention on the Law of the Sea, Art. 125(1), UN Doc. A/CONF. 62/122 (1982) [hereinafter UNCLOS].

²⁵ See Obligation to Negotiate Access to the Pacific Ocean (Bol. v. Chile), Judgment, at 54, para. 175 (Int'l Ct. Just. Oct. 1, 2018) [hereinafter Obligation to Negotiate Access].

²⁶ See Alvarez, José, Multilateralism and Its Discontents, 11 Eur. J. Int'l L. 393, 394 (2000)CrossRefGoogle Scholar (characterizing multilateralism as the “shared secular religion” of international lawyers).

²⁷ See Vienna Convention on the Law of Treaties, Art. 2(a), May 23, 1969, 1155 UNTS 331 (entered into force Jan. 27, 1980) [hereinafter VCLT]; Vienna Convention on the Law of Treaties Between States and International Organizations, Art. 2(a), UN Doc. A/CONF.129/15 (1986).

²⁸ See, e.g., Nuclear Tests Case (Austl./Fr.), Judgment, 1974 ICJ Rep. 253, para. 43 (Dec. 20) (“It is well recognized that declarations made by way of unilateral acts … may have the effect of creating legal obligations.”).

²⁹ See Guiding Principles Applicable to Unilateral Declarations of States Capable of Creating Legal Obligations, with Commentaries Thereto, at 379, UN Doc. A/61/10 (2006) (“No obligation may result for other States from the unilateral declaration of a State.”).

³⁰ See Consolidated Version of the Treaty on the European Union, Art. 49, Mar. 30, 2010, 2010 OJ (C 83) 13 (outlining application procedures for states to join the European Union); WTO Agreement, Art. XII, Apr. 15, 1994, Marrakesh Agreement Establishing the World Trade Organization, 1867 UNTS 154 (providing conditions for accession to the WTO).

³¹ President Thomas Jefferson, First Inaugural Address (Mar. 4, 1801).

³² See Arbitration Between the Republic of Croatia and the Republic of Slovenia, PCA Case No. 2012-04, Final Award, at 108, para. 334 (June 29, 2017) (describing mutual state consent as “the fundamental principle applicable to the establishment of land boundaries between sovereign States”); Steven R. Ratner, Land Feuds and Their Solutions: Finding International Law Beyond the Trial Chamber, 100 AJIL 808, 811 (2006) (“[T]he belief by one state that it has legal title to the territory of another does not legitimate the unilateral use of force. . .” (citation omitted)).

³³ See North Sea Continental Shelf Cases (Ger./Den.; Ger./Neth.), 1969 ICJ Rep. 3, 46, para. 85 (Feb. 20) [hereinafter North Sea Continental Shelf Cases] (holding that maritime “delimitation must be the object of agreement between the States concerned … in accordance with equitable principles”).

³⁴ Maritime Delimitation in the Area Between Greenland and Jan Mayen Case (Den. v. Nor.), 1993 ICJ Rep. 59, para. 48 (June 14); see also Case Concerning Delimitation of the Maritime Boundary in the Gulf of Maine Area (Can./U.S.), Judgment, 1984 ICJ Rep. 246, 299, para. 112 (Oct. 12) [hereinafter Gulf of Maine] (“No maritime delimitation between States with opposite or adjacent coasts may be effected unilaterally by one of those States. Such delimitation must be sought and effected by means of an agreement … [or] by recourse to a third party possessing the necessary competence.”).

³⁵ See Fisheries Case (U.K./Nor.), Judgment, 1951 ICJ Rep. 116, 132 (Dec. 18).

³⁶ Gulf of Maine, 1984 ICJ Rep. at 299, paras. 111–12.

³⁷ See Charter of Economic Rights and Duties of States, Art. 3, GA Res. 3281 (XXIX), 29 UN GAOR Supp. (No. 31), at 52, UN Doc. A/9631 (1974) [hereinafter Charter of Economic Rights and Duties] (“In the exploitation of natural resources shared by two or more countries, each State must co-operate on the basis of a system of information and prior consultations in order to achieve optimum use of such resources without causing damage to the legitimate interest of others.”); GA Res. 3129 XXVII, para. 2, 28 UN GAOR Supp. (No. 30), at 48, UN Doc. A/9030 (1973) [hereinafter GA Res. 3129] (affirming the same).

³⁸ See, e.g., Case Concerning Pulp Mills (Arg. v. Uru.), Judgment, 2010 ICJ Rep. 14, 76, para. 184 (Apr. 20) [hereinafter Pulp Mills] (concluding that the 1975 Statute of the River Uruguay cannot be satisfied “through the individual action of [either Uruguay or Argentina], acting on its own,” but rather “requires co-ordination”—including information exchange, consultation, and negotiation—“for the sustainable management and environmental protection of the river”).

³⁹ See The Law of the Non-Navigational Uses of International Watercourses, Art. 3, para. 34, in Report of the International Law Commission on the Work of Its Thirty-Second Session, [1980] 2 Y.B. Int'l L. Comm'n 114–18, paras. 16–36, UN Doc. A/CN.4/SER.A/1980/Add.1 [hereinafter International Watercourses] (concluding that the duty to negotiate over shared resources “flows from customary international law in the light of its current development”); Handl, Gunther, Binational Uses of Transboundary Air Resources: The International Entitlement Issue Reconsidered, 26 Natural Res. J. 405, 411 (1986)Google Scholar (“Today it is generally accepted that if a utilization of a natural resource in one jurisdiction affects a similar or different utilization in another, states are subject to mutually operating restraints as a matter of customary international law.”).

⁴⁰ (U.K./Ice.), Judgment, 1974 ICJ Rep. 3 (July 25) [Fisheries-Iceland]; (Ger./Ice.), Judgment, 1974 ICJ Rep. 175 (July 25) [Fisheries-Germany].

⁴¹ Fisheries-Iceland, 1974 ICJ at 27, para. 62; Fisheries-Germany, 1974 ICJ Rep. at 196, para. 54.

⁴² Id.

⁴³ Fisheries-Iceland, 1974 ICJ Rep. at 26, para. 57; Fisheries-Germany, 1974 ICJ Rep. at 194, para. 49.

⁴⁴ Id. In a similar spirit, the UN Convention on the Law of the Sea provides that states must “cooperate directly or through appropriate international organizations with a view to ensuring conservation and promoting the objective of optimum utilization of [highly migratory] species.” UNCLOS, supra note 24, Art. 64.

⁴⁵ See, e.g., Artic Sunrise Arbitration (Neth./Russ.), Case No. 2014-02, Award on the Merits, paras. 211, 230 (Perm. Ct. Arb. 2015) [hereinafter Arctic Sunrise Arbitration] (holding that Russia's right “to ensure the safety both of navigation and of the artificial islands, installations and structures” within its EEZ must be exercised with “due regard to the rights and duties of other States,” and that this right does not justify boarding a foreign vessel in the EEZ without the flag state's consent).

⁴⁶ Dispute Regarding Navigational and Related Rights (Costa Rica/Nicar.), Judgment, 2009 ICJ Rep. 213 (July 13) [hereinafter Dispute Regarding Navigational and Related Rights].

⁴⁷ Id. at 251–52, paras. 94–97.

⁴⁸ Id. at 257–58, paras. 112–15; cf. Artic Sunrise Arbitration, Case No. 2014-02, at paras. 233, 244.

⁴⁹ Dispute Regarding Navigational and Related Rights, 2009 ICJ Rep. at 252, para. 95.

⁵⁰ For an introduction to these concepts, see Brunnée, Jutta, Common Areas, Common Heritage, and Common Concern, in The Oxford Handbook of International Environmental Law 550 (Bodansky, Daniel, Brunnée, Jutta & Hey, Ellen eds., 2007)Google Scholar.

⁵¹ See, e.g., Fisheries-Iceland, 1974 ICJ Rep. at 96–97 (de Castro, J., separate opinion) (explaining that the high seas “belong to the community of peoples, or to mankind”); see generally Susan J. Buck, The Global Commons: An Introduction (1998); Hugo Grotius, The Freedom of the Seas 22–44 (James Brown & Scott eds., Ralph Van Deman Magoffin trans., 1916) (1609).

⁵² UNCLOS, supra note 24, Art. 118. As of January 1, 2019, UNCLOS has 168 parties. For a current list, see https://treaties.un.org/pages/ViewDetailsIII.aspx?src=TREATY&mtdsg_no=XXI-6&chapter=21&Temp=mtdsg3&clang=_en#1. Even non-parties tend to recognize that the vast majority of UNCLOS’s provisions reflect customary international law. See, e.g., President Ronald Reagan, Statement on United States Ocean Policy, 1983 Pub. Papers 378 (Mar. 10, 1983) (acknowledging that most UNCLOS provisions “confirm existing maritime law and practice and fairly balance the interests of all states”). The ICJ also has accepted key provisions of UNCLOS as customary international law, including articles that deal with maritime delimitation, fisheries, the continental shelf, and the high seas. See Roach, J. Ashley, Today's Customary International Law of the Sea, 45 Ocean Dev. & Int'l L. 239 (2014)CrossRefGoogle Scholar (collecting cases).

⁵³ See Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, Art. II, Jan. 27, 1967, 18 UST 2410, 610 UNTS 205 [hereinafter Outer Space Treaty].

⁵⁴ Id. Art. IX. There is deep tension between this and other requirements of the Outer Space Treaty, on the one hand, and the idea that one nation might develop a military “space force” to assert dominance of outer space, on the other. See Betsy Klein, Trump: Space Force and Air Force Will Be “Separate but Equal,” CNN (June 18, 2018), at https://www.cnn.com/2018/06/18/politics/trump-space-force-air-force/index.html.

⁵⁵ See Antarctic Treaty, Art. IV, Dec. 1, 1959, 12 UST 794, 402 UNTS 71. Although territorial claims have been made for much of the continent, “these have been frozen since the adoption of the Antarctic Treaty.” Brunnée, supra note 50, at 561.

⁵⁶ See Antarctic Treaty, supra note 55, Art. IX.

⁵⁷ UNCLOS, supra note 24, Art. 136; see also Prows, Peter, Tough Love: The Dramatic Birth and Looming Demise of UNCLOS Property Law (And What Is to Be Done About It), 42 Tex. Int'l L.J. 241, 244 (2007)Google Scholar (distinguishing the res publica omnium regime for deep sea minerals from the res communis regime for the high seas).

⁵⁸ See UNCLOS, supra note 24, Art. 140 (providing that such “[a]ctivities in the [seabed and ocean floor below the high seas] shall … be carried out for the benefit of mankind as a whole” and distributed according to the principles of “equitable sharing” and non-discrimination).

⁵⁹ See Convention for the Protection of Cultural Property in the Event of Armed Conflict with Regulations for the Execution of the Convention 1954, pmbl. (May 14, 1954) (explaining that states must respect and protect important cultural works because “damage to cultural property belonging to any people whatsoever means damage to the cultural heritage of all mankind”).

⁶⁰ See Brunnée, supra note 50, at 563 (noting that “the very countries most likely to” exploit the deep seabed “have consistently resisted the application of the concept”).

⁶¹ See, e.g., Adoption of the Paris Agreement, pmbl., FCCC/CP/2015/L.9/Rev.1 (Dec. 12, 2015); The World Conservation Union & International Council of Environmental Law, Draft International Covenant on Environment and Development, Art. 3 & cmt. at 38–39 (4th ed. 2010) (characterizing the global environment as a “common concern of humanity” and stating that this status “implies acceptance of both the right and the duty of the international community as a whole to have concern for the global environment”).

⁶² Rio Declaration on Environment and Development, Principle 7, adopted June 14, 1992, UN Doc. A/CONF.151/26 (1992). For similarly broad pronouncements describing the global environment as a common concern triggering mandatory multilateralism, see MOX Plant Case (Ireland/U.K.), ITLOS No. 10, para. 82 (Dec. 3, 2001) [hereinafter MOX Plant Case] (characterizing the “duty to cooperate” in protecting the global environment as “a fundamental principle” of “general international law”); id. at 135 (Wolfrum, J., separate opinion) (“The obligation to cooperate with other States whose interests may be affected is a Grundnorm of [UNCLOS], as of customary international law for the environment.”).

⁶³ UNFCCC, supra note 23, pmbl. (emphasis added); see also Brunnée, supra note 50, at 564–565 (emphasizing this limitation).

⁶⁴ UN Conference on Environment and Development: Convention on Biodiversity, pmbl., opened for signature June 5, 1992, 31 ILM 822 (emphasis added).

⁶⁵ UN Charter Art. 1.

⁶⁶ See id. Arts. 39–42 (providing for the Security Council to determine what measures are necessary to maintain or restore international peace and security).

⁶⁷ Id. Art. 2(3); see also id. Art 33(1) (“The parties to any dispute, the continuance of which is likely to endanger the maintenance of international peace and security, shall, first of all, seek a solution by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies or arrangements, or other peaceful means of their own choice.”).

⁶⁸ Id. Art. 2(4).

⁶⁹ Id. Art. 37.

⁷⁰ Id. Art. 2(5); see also Art. 48(1) (providing that “action required to carry out the decisions of the Security Council for the maintenance of international peace and security shall be taken by all the Members of the United Nations or by some of them, as the Security Council may determine”); id. Art. 49 (“The Members of the United Nations shall join in affording mutual assistance in carrying out the measures decided upon by the Security Council.”).

⁷¹ Id. Art. 2(6).

⁷² Id. Arts. 39–42.

⁷³ See id. Art. 51 (“Nothing in the present Charter shall impair the inherent right of individual or collective self-defence if an armed attack occurs against a Member of the United Nations, until the Security Council has taken measures necessary to maintain international peace and security… .”).

⁷⁴ Id.

⁷⁵ Id. Although the Charter does not expressly address imminent attacks, conventional wisdom holds that Article 51 permits self-defense in response to imminent attacks. See, e.g., Christine Gray, International Law and the Use of Force 161 (3d ed. 2008); Yoram Dinstein, War, Aggression and Self-Defence 168 (3d ed. 2001).

⁷⁶ UN Charter Art. 51.

⁷⁷ Id. Art. 1(3).

⁷⁸ Id. Art. 56.

⁷⁹ Id. Art. 55.

⁸⁰ See id. Art. 60 (assigning responsibility to the General Assembly and ECOSOC to discharge this coordination function).

⁸¹ Universal Declaration of Human Rights, UNGA Res. 217 A (III), UN Doc. A/810 (1948) [hereinafter UDHR].

⁸² International Covenant on Civil and Political Rights, Dec. 16, 1966, 999 UNTS 171.

⁸³ International Covenant on Economic, Social and Cultural Rights, Dec. 16, 1966, 993 UNTS 3.

⁸⁴ See, e.g., SC Res. 2085, para. 9 (Dec. 20, 2012) (authorizing “the deployment of an African-led International Support Mission in Mali” to support local authorities’ efforts to protect civilians); SC Res. 1970 (Feb. 26, 2011) (imposing sanctions in response to crimes against humanity in Libya); SC Res. 1962, pmbl., paras. 3, 14, 15 (Dec. 20, 2010) (authorizing military action for the protection of civilians in Côte d'Ivoire).

⁸⁵ See UN Charter Art. 25 (“The Members of the United Nations agree to accept and carry out the decisions of the Security Council in accordance with the present Charter.”). The UN General Assembly and Human Rights Council have affirmed repeatedly that international human rights trigger positive duties of international cooperation. See, e.g., Human Rights Council Res. 35/8, para. 8, UN Doc. A/HRC/RES/35 (July 14, 2017) (emphasizing “the duty of States to cooperate with one another in accordance with the Charter of the United Nations in the promotion of universal respect for and observance of human rights and fundamental freedoms”); 2005 UN Secretary-General, Implementing the Responsibility to Protect, para. 10, UN Doc. A/63/677 (2009) (embracing this principle); World Summit Outcome, GA Res. 60/1, para. 139 (Oct. 24, 2005) (“The international community, through the United Nations,” bears “responsibility … to help to protect populations from genocide, war crimes, ethnic cleansing and crimes against humanity.”); GA Res. 48/121 (Dec. 20, 1993) (endorsing the Vienna Declaration and Programme of Action, A/Conf.157/23 (July 12, 1993), which affirms “the commitment contained in Article 56 of the Charter of the United Nations to take joint and separate action, placing proper emphasis on developing effective international cooperation for the realization of the purposes set out in Article 55, including universal respect for, and observance of, human rights and fundamental freedoms for all”); GA Res. 47/131, para. 3 (Dec. 18, 1992) (calling upon UN “Member States to base their activities for the protection and promotion of human rights, including the development of further international cooperation … , on the Charter … and other relevant international instruments”).

⁸⁶ International Law Commission, Articles on Responsibility of States for Internationally Wrongful Acts, Arts. 40–41, in Report of the International Law Commission on the Work of Its Fifty-Third Session, UN GAOR, 56th Sess., Supp. No. 10, at 113, UN Doc. A/56/10 (2001); see also id. Art. 41, cmt. 3 (“What is called for in the case of serious breaches, is a joint and coordinated effort by all States to counteract the effects of these breaches.”). According to the ILC, this duty to cooperate in suppressing serious abuses complements states’ Charter-based duty to contribute to multilateral action through the United Nations. See id. cmt. 2 (“Cooperation could be organized in the framework of a competent international organization, in particular the United Nations. However, paragraph 1 also envisages the possibility of non-institutionalized cooperation.”). Accordingly, even when the Security Council fails to take action, the Articles suggest that states are duty-bound to cooperate with one another to safeguard human rights as well as the individual and collective interests protected under international criminal law.

⁸⁷ Id. Art. 41, cmt. 3.

⁸⁸ Id.

⁸⁹ See Hakimi, Monica, Toward a Legal Theory on the Responsibility to Protect, 39 Yale J. Int'l L. 247, 254 (2014)Google Scholar (“The claim that [the responsibility to protect] demands action by all outside states simultaneously has some authoritative support but remains almost entirely aspirational.”); Payandeh, Mehrdad, Note, With Great Power Comes Great Responsibility? The Concept of the Responsibility to Protect Within the Process of International Lawmaking, 35 Yale J. Int'l L. 469, 480–85 (2010)Google Scholar (questioning whether the responsibility to protect concept has received sufficient definition to qualify as customary international law).

⁹⁰ Cf. Application of Convention on Prevention and Punishment of Crime of Genocide (Bosn. & Herz. v. Serb. & Montenegro), 2007 ICJ Rep. 47, 221, para. 430, 225, para. 438 (Feb. 26) (holding that parties to the Genocide Convention bear a duty of “due diligence” to use all lawful tools at their disposal to prevent genocide abroad, and faulting Yugoslav federal authorities for violating this obligation); Basic Principles and Guidelines on the Right to a Remedy and Reparation for Victims of Gross Violations of International Human Rights Law and Serious Violations of International Humanitarian Law, GA Res. 60/147, at 5, para. 4 (Mar. 21, 2006) (“In cases of gross violations of international human rights law and serious violations of international humanitarian law constituting crimes under international law, … States should, in accordance with international law, cooperate with one another and assist international judicial organs competent in the investigation and prosecution of these violations.”).

⁹¹ UN Charter Art. 33(1).

⁹² Dispute Regarding Navigational and Related Rights, 2009 ICJ Rep. at 252, para. 95.

⁹³ See, e.g., Gulf of Maine, 1984 ICJ Rep. at 299–300, paras. 111–13.

⁹⁴ Oxford Reference, at http://www.oxfordreference.com/view/10.1093/oi/authority.20110803100306400.

⁹⁵ 3 Emer de Vattel, The Law of Nations or the Principles of Natural Law: Applied to the Conduct and to the Affairs of Nations and of Sovereigns 75, § 18 (Bela Kapossy & Richard Whatmore eds., 2008) (1797).

⁹⁶ Edwin DeWitt Dickinson, The Equality of States in International Law 3, 102 (1920); see also Lassa Oppenheim, 1 International Law: A Treatise 238, § 115 (Hersch Lauterpacht ed., 6th ed. 1947) (“The equality before International Law of all member-States of the Family of Nations is an invariable quality derived from their International Personality.”).

⁹⁷ Robert A. Klein, Sovereign Equality Among States: The History of an Idea (1974) (chronicling resistance to sovereign equality prior to and during the creation of the United Nations). The point of this paragraph is to acknowledge the historical background and power politics that at times frustrated the entrenchment of sovereign equality as an organizing principle of international law, but without prejudice to the constitutional role sovereign equality would eventually come to play as an organizing principle.

⁹⁸ Id. at 50–51.

⁹⁹ Id. at 54–61.

¹⁰⁰ Id. at 67–139.

¹⁰¹ Oona A. Hathaway & Scott J. Shapiro, The Internationalists: How a Radical Plan to Outlaw War Remade the World 187 (2017).

¹⁰² UN Charter Art. 23.

¹⁰³ Id. Art. 2(1).

¹⁰⁴ UN General Assembly, Declaration on Principles of International Law Concerning Friendly Relations and Co-operation Among States in Accordance with the Charter of the United Nations, UN Doc. A/RES/25/2625 (Oct. 24, 1970) [hereinafter Friendly Relations Declaration].

¹⁰⁵ Id.

¹⁰⁶ Babovic, Bogdan, The Duty of States to Cooperate with One Another in Accordance with the Charter, in Principles of International Law Concerning Friendly Relations and Cooperation 281–83 (Sahovic, Milan ed., 1972)Google Scholar.

¹⁰⁷ Friendly Relations Declaration, supra note 104, pmbl.

¹⁰⁸ Jurisdictional Immunities of the State (Ger. v. It.; Greece intervening), 2012 ICJ Rep. 99, para. 57 (Feb. 3); see also Oppenheim, supra note 96, at 196, § 115 (“The equality before International Law of all member-States of the Family of Nations is an invariable quality derived from their International Personality.”).

¹⁰⁹ The Case of the S.S. Lotus, 1927 PCIJ (Ser. A) No. 10 (Sept. 7) [hereinafter Lotus].

¹¹⁰ Id. at 44 (dissenting, but not on this point).

¹¹¹ Preuss, U.K., Equality of States – Its Meaning in a Constitutionalized Global Order, 9 Chi. J. Int'l L. 17, 26 (2008)Google Scholar.

¹¹² But see id. at 42 (arguing that under the League “submission of disputes to the judgment of international courts … was strictly voluntary,” and so “the League's mode of decisionmaking” was not “collective” but rather “a mere mechanism of coordinating the obligations of independent states”).

¹¹³ For discussion of these developments, see the essays collected in Ruling the World? Constitutionalism, International Law, and Global Governance (Jeffrey L. Dunoff & Joel P. Trachtman eds., 2012).

¹¹⁴ Brad R. Roth, Sovereign Equality and Moral Disagreement: Premises of a Pluralist International Legal Order 13 (2011).

¹¹⁵ Hart, H.L.A., Positivism and the Separation of Law and Morals, 71 Harv. L. Rev. 593, 603 (1958)CrossRefGoogle Scholar (critiquing John Austin's command theory of law according to which law consists in commands backed by force of an uncommanded commander).

¹¹⁶ Status of Eastern Carelia, Advisory Opinion, 1923 PCIJ (Ser. B) No. 5, at 27 (July 23) [hereinafter Status of Eastern Carelia].

¹¹⁷ Some more radical political voluntarists are skeptics regarding international law, arguing that treaties and customary law are not really law but rather expressions of, at most, political or moral obligations. See, e.g., Bolton, John R., Is There Really “Law” in International Affairs?, 10 Transnat'l L. & Contemp. Probs. 1, 4–7 (2000)Google Scholar.

¹¹⁸ Lotus, 1927 PCIJ (Ser. A) No. 10.

¹¹⁹ Weil, Prosper, “The Court Cannot Conclude Definitively” … Non Liquet Revisited, 36 Colum. J. Transnat'l L. 109, 112 (1998)Google Scholar.

¹²⁰ Lotus, 1927 PCIJ (Ser. A) No. 10, at 18.

¹²¹ Id. at 19. But see Hertogen, An, Letting Lotus Bloom, 26 Eur. J. Int'l L. 901, 904 (2016)CrossRefGoogle Scholar (arguing that Lotus has been misinterpreted and that the key to understanding the case lies in the Court's commitment to the “co-existence of independent communities”).

¹²² Weil, supra note 119, at 113.

¹²³ See, e.g., Klabbers, Jan, On Responsible Global Governance, in Towards Responsible Global Governance 11, 29 (Klabbers, Jan, Varaki, Maria & Vilaça, Guilherme Vasconcelos eds., 2018)Google Scholar (characterizing the constitutionalist idea of responsible governance as a “sensibility”); Koskenniemi, Martti, Constitutionalism as Mindset: Reflections on Kantian Themes About International Law and Globalization, 8 J. Theoretical Inq. L. 9 (2007)Google Scholar.

¹²⁴ See, e.g., Bogdandy, Armin von, Constitutionalism in International Law: Comment on a Proposal from Germany, 47 Harv. Int'l L.J. 223, 226 (2006)Google Scholar (discussing Christian Tomuschat's constitutionalist account of international law as supporting human rights and the rule of law); Kumm, Mattias, The Legitimacy of International Law: A Constitutionalist Framework Analysis, 15 Eur. J. Int'l L. 907 (2004)CrossRefGoogle Scholar (specifying human rights, democracy, and the rule of law as global constitutionalism's core values).

¹²⁵ Lotus, 1927 PCIJ (Ser. A) No. 10, at 35, para. 106.

¹²⁶ Id. at 35, para. 105; see also The Antelope, 23 U.S. 66, 122 (1825) (“No principle of general law is more universally acknowledged, than the perfect equality of nations… . It results from this equality, that no one can rightfully impose a rule on another. Each legislates for itself, but its legislation can operate on itself alone.”).

¹²⁷ Lotus, 1927 PCIJ (Ser. A) No. 10, at 35.

¹²⁸ We discuss this conception of freedom as independence as it pertains to human rights bearers in Criddle, Evan Fox-Decent & Evan J., The Fiduciary Constitution of Human Rights, 15 Legal Theory 301, 310–11 (2009)Google Scholar. The “liberal” and “republican” nomenclature is standard in writings on liberty that, on the one hand, distinguish liberal “negative” or non-interference conceptions of liberty from positive “freedom from” conceptions, and, on the other, distinguish non-interference accounts of liberty from republican or neo-Roman accounts that focus on the evil domination. See, e.g., Isaiah Berlin, Two Concepts of Liberty (1958) (distinguishing negative and positive conceptions of liberty); Philip Pettit, Republicanism: A Theory of Freedom and Government (1997) (developing a republican theory of freedom based on the ideal of non-domination).

¹²⁹ By “fair terms of cooperation” we have in mind something like the reciprocal terms on which free and equal persons might interact under Rawls's conception of justice as fairness. See, e.g., John Rawls, Justice as Fairness 6 (2001) (distinguishing social coordination from social cooperation).

¹³⁰ UN General Assembly, Declaration on the Inadmissibility of Intervention in the Domestic Affairs of States and the Protection of Their Independence and Sovereignty, para. 1, Dec. 21, 1965, A/RES/2131(XX).

¹³¹ Id., paras. 1–3.

¹³² Id., para. 1.

¹³³ Id., para. 2. References to “subordination” and securing “advantages” suggest that the coercion referred to in this provision relates more to the threat than the use of force.

¹³⁴ Id., para. 6.

¹³⁵ One can attack the unilateral-act/threat-of-unilateral-act distinction by saying that a threat to act unilaterally is itself a unilateral act. See Matthew H. Kramer, The Quality of Freedom, at ch. 2 (2003). The distinction we are making, however, is substantive rather than linguistic or semantic, and could be recast as “actual unilateralism” versus “promised-and-realizable-but-as-yet-unrealized unilateralism.” For simplicity, we will stick with “act” and “threat” to mark these categories.

¹³⁶ See, e.g., Quentin Skinner, Liberty Before Liberalism (1998); Pettit, supra note 128.

¹³⁷ See, e.g., Pettit, supra note 128, at 133, 184.

¹³⁸ See Thomas Hobbes, Leviathan with Selected Variants from the Latin Edition of 1668, at ch. 16 (Edwin Curely ed., 1994). Compare Skinner, Quentin, Hobbes and the Purely Artificial Person of the State, 7 J. Pol. Phil 1 (1999)CrossRefGoogle Scholar; with Runciman, David, What Kind of Person Is Hobbes's State? A Reply to Skinner, 8 J. Pol. Phil 268 (2000)CrossRefGoogle Scholar.

¹³⁹ Kelsen, Hans, The Principle of Sovereign Equality of States as a Basis for International Organization, 53 Yale L.J. 207, 208 (1944)CrossRefGoogle Scholar.

¹⁴⁰ Lake Lanoux Arbitration (Fr. v. Sp.), 24 ILR 101, 102–03 (1957) [hereinafter Lake Lanoux Arbitration].

¹⁴¹ Id. at 101.

¹⁴² Id. at 101–02.

¹⁴³ Id. at 102–05.

¹⁴⁴ Id. at 102–03.

¹⁴⁵ Id. at 103.

¹⁴⁶ Id. at 105.

¹⁴⁷ Id. at 120.

¹⁴⁸ Id. at 117–19.

¹⁴⁹ International Watercourses, supra note 39, at 117, para. 34.

¹⁵⁰ Lac Lanoux Arbitration, 24 ILR at 128.

¹⁵¹ Id.

¹⁵² Id.

¹⁵³ Id. at 129.

¹⁵⁴ Id. at 130.

¹⁵⁵ Id. at 139.

¹⁵⁶ Id.

¹⁵⁷ Id. at 142.

¹⁵⁸ Id. at 128.

¹⁵⁹ Id. at 138–42.

¹⁶⁰ Id. at 113.

¹⁶¹ Id. at 125–26.

¹⁶² See supra Part II.

¹⁶³ See, e.g., Robert McCorquodale, International Law Beyond the State: Essays on Sovereignty, Non-state Actors, and Human Rights (2011) (discussing how international law has moved well beyond interstate law).

¹⁶⁴ UNCLOS, supra note 24, Art. 74(1).

¹⁶⁵ Id. Art. 74(2).

¹⁶⁶ See Evan J. Criddle & Evan Fox-Decent, Fiduciaries of Humanity: How International Law Constitutes Authority, at chs. 6–8 (2016). For discussion of the way in which a fiduciary can owe duties to both discrete beneficiaries and a wider public, see Criddle, Evan J. & Fox-Decent, Evan, Guardians of Legal Order: The Dual Commissions of Public Fiduciaries, in Fiduciary Government 67 (Criddle, Evan J., Fox-Decent, Evan, Gold, Andrew S., Kim, Sung Hui & Miller, Paul B. eds., 2018)CrossRefGoogle Scholar.

¹⁶⁷ Benvenisti, Eyal, Sovereigns as Trustees of Humanity: On the Accountability of States to Foreign Stakeholders, 107 AJIL 295, 314 (2013)CrossRefGoogle Scholar; see also Fox-Decent, Evan, From Fiduciary States to Joint Trusteeship of the Atmosphere: The Right to a Healthy Environment Through a Fiduciary Prism, in Fiduciary Duty and the Atmospheric Trust 253 (Coghill, Ken, Sampford, Charles & Smith, Tim eds., 2012)Google Scholar (arguing that states are joint trustees of the atmosphere on behalf of humanity); Criddle, Evan J. & Fox-Decent, Evan, A Fiduciary Theory of Jus Cogens, 34 Yale J. Int'l L. 331, 380–82 (2009)Google Scholar (discussing state obligations to respect the human rights of resident non-citizens, extraterritorially detained foreign nationals, and refugees); Fox-Decent & Criddle, supra note 128, at 301 (arguing that “human rights are best conceived as norms arising from a fiduciary relationship that exists between states (or statelike actors) and the citizens and noncitizens subject to their power”).

¹⁶⁸ Benvenisti, supra note 167, at 320 (emphasis in original). By “with no compensation” Benvenisti means that the sovereign cannot be made to suffer a loss and then compensated after the fact, which is how the ordinary Pareto criterion works. His “restricted” criterion is intended to be less onerous on sovereigns asked to take account of foreign interests.

¹⁶⁹ Id. at 307 (citing UDHR, supra note 81, pmbl.).

¹⁷⁰ Benvenisti disagrees, arguing that the restricted Pareto criterion “was probably … an influential consideration” in Lac Lanoux because “France benefited … whereas Spain sustained no loss.” Id. at 323. Benvenisti arguably misapplies his criterion to the case. The criterion is intended to comfort sovereigns called on to take account of foreign nationals’ interests, such as sovereigns of coastal states petitioned to allow access through maritime straits. In Lac Lanoux, the proper subject of the “no loss” proviso is France, since France alone has sovereign rights over the waterways within its territory, and France alone is called on to exercise those rights in a manner respectful of foreign interests. The appropriate question under Benvenisti's theory is whether France would sustain any loss by ensuring that its diversion of the waterway did not impair Spanish interests. It is evident from the facts that France incurred significant cost in order to accommodate Spanish interests. France installed an engineered tunnel to return the diverted water to its natural destination. The negotiations alone extended over decades. It is hard to see how the “no loss” criterion could explain the legal requirement of ongoing and costly negotiations, or (had France done nothing to accommodate Spain) an arbitral award that France provide infrastructure to protect the interests of downstream Spanish nationals.

¹⁷¹ See, e.g., New York Declaration for Refugees and Migrants, GA Res. 71/1, para. 11 (Sept. 19, 2016) (“We acknowledge a shared responsibility to manage large movements of refugees and migrants in a humane, sensitive, compassionate and people–centred manner. We will do so through international cooperation … .”). Admittedly, the present weakness of the international refugee law regime, which imposes on states a duty of non-refoulement rather than a duty to grant asylum, serves as a reminder that it can take time for multilateral legal regimes to embody fully the norms of their underlying presuppositions. See Convention Relating to the Status of Refugees, Art. 33(1), July 28, 1951, 189 UNTS 150 (entered into force Oct. 4, 1954) (enshrining the duty of non-refoulement).

¹⁷² UN Charter Art. 2(4).

¹⁷³ See UNCLOS, supra note 24, Art. 38 (providing for transit rights through international straits); Case Concerning Passage Through the Great Belt (Fin. v. Den.), Order on Provisional Measures, 1991 ICJ Rep. 12, 18, para. 26 (July 29) (provisionally rejecting the proposition “that interference with the right [to transit passage] might be justified on the grounds that the passage … might be achieved by other means, which may moreover be less convenient or more costly”).

¹⁷⁴ Restatement (Third) of Foreign Relations of the United States, § 702 cmts. d–i, § 102 cmt. k (1987).

¹⁷⁵ See, e.g., A. Mark Weisburd, American Judges and International Law, 36 Vand. J. Transnat'l L. 1475, 1493 (2003) (observing that state delegations at the Vienna Conference on the Law of Treaties in 1969 “offered widely differing lists of rules meeting the requirements of jus cogens; of the twenty-six delegations … no more than thirteen agreed with respect to any one rule”).

¹⁷⁶ In Part V, we discuss Bolivia v. Chile as an example: Chile is under no obligation to negotiate cession of its territory to Bolivia.

¹⁷⁷ North Sea Continental Shelf Cases, 1969 ICJ Rep. at 47, para. 86 (citing UN Charter Art. 33). To the extent that international law commits certain natural resources, such as international lakes and rivers, to the environmental stewardship of adjacent states, mandatory multilateralism in these contexts also reflects the principle of joint stewardship.

¹⁷⁸ See, e.g., UNCLOS, supra note 24, Art. 157(3) (providing that decision making by the International Seabed Authority, which coordinates mining operations in the deep seabed, a common heritage resource, “is based on the principle of the sovereign equality of all its members”); Rio Declaration on Environment and Development, Principle 12, UN Conference on Environment and Development, UN Doc. A/Conf.151/5/Rev.1 (1992) [hereinafter Rio Declaration] (“Unilateral actions to deal with environmental challenges outside the jurisdiction of the importing country should be avoided. Environmental measures addressing transboundary or global environmental problems should, as far as possible, be based on international consensus.”).

¹⁷⁹ For reasons of space, the cases discussed in this Part are drawn from the first three categories of mandatory multilateralism: jurisdictional disputes, conflicting legal entitlements, and common resources. Within international human rights regimes, principles of proportionality and due process arguably supply content to mandatory multilateralism's requirements. Principles such as these elicit due regard for foreign nationals touched by sovereign power, and they help to explain the European Court of Human Rights’ understanding of itself as the guardian of a “constitutional instrument of European public order (ordre public).” Loizidou v. Turkey, 310 Eur. Ct. H.R. (ser. A) para. 75 (1995).

¹⁸⁰ See, e.g., Request for an Advisory Opinion Submitted by the Sub-Regional Fisheries Commission (SRFC), Advisory Opinion of 2 April 2015, ITLOS Rep. 2015, para. 219; Arctic Sunrise Arbitration, Case No. 2014-02, at paras. 228, 230, (Perm. Ct. Arb. 2015); Chagos Marine Protected Area Arbitration (Mauritius/U.K.), Case No. 2011-03, Award, para. 534 (Perm. Ct. Arb. 2015) [hereinafter Chagos]; Fisheries-Germany, 1974 ICJ Rep. at 198, para. 60. We here make common cause with Benvenisti who avers “[a]s trustees of humanity, national decision makers have an obligation to take into account the interests of others when devising policies.” Benvenisti, supra note 167, at 314.

¹⁸¹ See, e.g., World Trade Organization, United States – Import Prohibition of Certain Shrimp and Shrimp Products, Report of the Appellate Body, paras. 158, 160, AB-1998-4, WT/DS58/AB/R (Oct. 12, 1998) [hereinafter Shrimp/Turtle Appellate Body Report I]; WTO, United States – Import Prohibition of Certain Shrimp and Shrimp Products, Recourse to Art. 21.5 by Malaysia, Report of the Panel, paras. 5.51–.60, WT/DS58/RW (June 15, 2001) [hereinafter Shrimp/Turtle Panel Report II]; see generally Robert Kolb, Good Faith in International Law 142–45 (2017) (discussing international “abuse of right” as including “manifest disproportion of interests” and “arbitrary action”); id. at 198–99 (describing the applications of good faith in international jurisprudence).

¹⁸² See, e.g., Chagos, Case No. 2011-03, at para. 534 (observing that the duty of “due regard” for another state's interests “entails, at least, both consultation and a balancing exercise with its own rights and interests”).

¹⁸³ See Gulf of Maine, 1984 ICJ Rep. at 299–300, paras. 111–13 (characterizing “the application of equitable criteria” (i.e., substantive multilateralism) and consensus-based decision making or third-party dispute resolution (i.e., procedural multilateralism) as the “fundamental norm[s]” of international maritime delimitation).

¹⁸⁴ Gaunce, Julia, On the Interpretation of the General Duty of “Due Regard,” 32 Ocean Y.B. 27 (2018)Google Scholar.

¹⁸⁵ Fisheries-Germany, 1974 ICJ Rep. at 200, para. 62; see also North Sea Continental Shelf Cases, 1969 ICJ Rep. at 139–40, para. 38 (Ammoun, J., dissenting) (observing that equity is a general principle of law common to all of “the great legal systems of the modern world”).

¹⁸⁶ Lake Lanoux Arbitration, 24 ILR 101, at 139, para. 22.

¹⁸⁷ See, e.g., UNCLOS, supra note 24, Art. 58(3) (“In exercising their rights and performing their duties under this Convention in the exclusive economic zone, States shall have due regard to the rights and duties of the coastal State … .”); id. Art. 87(2) (providing that states’ freedoms in the high seas “shall be exercised by all States with due regard for the interests of other States in their exercise of the freedom of the high seas”); Convention on the High Seas, Art. 2, Apr. 29, 1958, 13 UST 2312, TIAS No. 5200, 450 UNTS 82 (providing that state freedoms on the high seas “shall be exercised by all States with reasonable regard to the interests of other States in their exercise of the freedom of the high seas”).

¹⁸⁸ See Fisheries-Iceland, 1974 ICJ Rep. at 27–28, para. 62, 29, para. 68 (applying Article 2 of the 1958 Geneva Convention).

¹⁸⁹ Id. at 28, para. 62.

¹⁹⁰ Id. at 33, para. 78.

¹⁹¹ Id.

¹⁹² Chagos, Case No. 2011-03, Award, at para. 534.

¹⁹³ Id., paras. 7–8.

¹⁹⁴ Id., paras. 518–19.

¹⁹⁵ Id., para. 519.

¹⁹⁶ Id.; see also South China Sea Arbitration, PCA Case No. 2013-19, Award, paras. 741–42 (July 12, 2016) [hereinafter South China Sea Arbitration] (discussing these aspects of the Chagos judgment); North Sea Continental Shelf Cases, 1969 ICJ Rep. at 46–47, para. 85 (holding that maritime delimitation “must be arrived at in accordance with equitable principles, … taking all the circumstances into account”).

¹⁹⁷ Shrimp/Turtle Appellate Body Report I, supra note 181, para. 159. Reflecting on this balancing act, a WTO dispute settlement panel later explained that “the position of the line itself depends on the type of measure imposed and on the particular circumstances of the case.” Shrimp/Turtle Panel Report II, supra note 181, para. 5.51. Ultimately in this case, the WTO's Appellate Body concluded that the United States’ revised certification process was sufficiently flexible to facilitate the requisite balancing. See WTO, United States – Import Prohibition of Certain Shrimp and Shrimp Products, Recourse to Art. 21.5 by Malaysia, Recourse to Art. 21.5 of the DSU by Malaysia, Report of the Appellate Body, paras. 123, 134, AB-2001-4, WT/DS58/AB/RW (Oct. 22, 2001) [hereinafter Shrimp/Turtle Appellate Body Report II]. This conclusion was predicated on the expectation that U.S. regulators would engage in further dialogue with their Malaysian counterparts during certification review, and that they ultimately would need to perform the delicate balancing exercise themselves if they hoped to defend their decisions successfully before the Appellate Body in the future.

¹⁹⁸ See Fisheries-Iceland, 1974 ICJ Rep. at 69–70 (Dillard, J., separate opinion) (observing that “[t]he obligation to pay due regard to the interests of other States … is, of course, a norm of law which lies upon all States” and “can be triggered by any State whose interests are allegedly infringed by another State involving thereby an obligation to come to some kind of peaceful arrangement”).

¹⁹⁹ In the case of land borders, equitable principles serve a modest role as an interstitial gap-filler when the principle of uti possidetis juris does not offer clear answers. See, e.g., Case Concerning the Frontier Dispute (Burk. Faso/Mali), 1986 ICJ Rep. 554, 633 paras. 149–50 (Dec. 22). Equitable principles find wider application in international maritime delimitation, where states often write on a clean slate. See supra text at notes 33–36.

²⁰⁰ See UNFCCC, supra note 23, Art. 3(1) (“The Parties should protect the climate system … on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities.”).

²⁰¹ See, e.g., Agreement on the Nile River Basin Cooperative Framework, Arts. 3(4), 4, available at http://internationalwaterlaw.org/documents/regionaldocs/Nile_River_Basin_Cooperative_Framework_2010.pdf (providing that apportionment of Nile waters would be based on the “principle of equitable and reasonable utilization”).

²⁰² See Criddle, William C. Banks & Evan J., Customary Constraints on the Use of Force: Article 51 with an American Accent, 29 Leiden J. Int'l L. 67, 74–75 (2016)Google Scholar (discussing jus ad bellum proportionality).

²⁰³ See Gulf of Maine, 1984 ICJ Rep. at 299–300, para. 112 (holding that maritime “delimitation is to be effected by the application of equitable criteria and by the use of practical methods capable of ensuring … an equitable result); Continental Shelf (Tunis./Libya), 1982 ICJ Rep. 18, 59, para. 70 (Feb. 24) (“The result of the application of equitable principles must be equitable… . The equitableness of a principle must be assessed in the light of its usefulness for the purpose of arriving at an equitable result.”).

²⁰⁴ Kolb, supra note 181, at 23. Kolb characterizes this requirement as “good faith,” rather than “due regard” or “equitable balancing.” Id.

²⁰⁵ Id. at 36–37.

²⁰⁶ Fisheries-Iceland, 1974 ICJ Rep. 3; Fisheries-Germany, 1974 ICJ Rep. 175.

²⁰⁷ Wolfgang Friedmann, The Changing Structure of International Law 61–62 (1964).

²⁰⁸ Fisheries-Iceland, 1974 ICJ Rep. at 31, para. 72; Fisheries-Germany, 1974 ICJ Rep. at 29, para. 64.

²⁰⁹ In the context of threats to international peace and security and serious abuses of international human rights, international law arguably requires states to conduct a thorough investigation and use force abroad only on the basis of “compelling evidence.” Schmitt, Michael N., U.S. Security Strategies: A Legal Assessment, 27 Harv. J. L. & Pub. Pol'y 737, 756–57 (2004)Google Scholar (endorsing this standard advanced by U.S. policymakers as consistent with international law).

²¹⁰ Fisheries-Iceland, 1974 ICJ Rep. at 31, para. 72; Fisheries-Germany, 1974 ICJ Rep. at 28, para. 64.

²¹¹ See, e.g., Chagos, Case No. 2011-03, at para. 519 (“In the majority of cases, [due regard for other states’ rights] will necessarily involve at least some consultation with the rights-holding State.”); id., para. 541 (recognizing that environmental concerns “require significant engagement with [other states] to explain the need for [measures infringing states’ fishing rights] and to explore less restrictive alternatives”); MOX Plant Case, ITLOS No. 10, at para. 84 (“[P]rudence and caution require that [states] cooperate in exchanging information concerning risks … and in devising ways to deal with them, as appropriate.”).

²¹² See, e.g., UN Charter Art. 51 (obligating states to report exercises of self-defense to the UN Security Council); UNCLOS, supra note 24, Arts. 61, 119, 200 (providing for sharing of “scientific information” and other “data” relevant to shared resources).

²¹³ See, e.g., Pulp Mills, 2010 ICJ Rep. at 40, para. 48; Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, 1996 ICJ Rep. 226, 263–64, paras. 99–103 (July 8); German External Debts Case (Greece/Ger.), 19 RIAA 27 (1972).

²¹⁴ See, e.g., North Sea Continental Shelf Cases, 1969 ICJ Rep. at 47, para. 86; see also Fisheries-Iceland, 1974 ICJ Rep. at 41 (Singh, J., separate opinion) (asserting that in a dispute over conflicting legal entitlements to fisheries “negotiations appear necessary and flow from the nature of the dispute”).

²¹⁵ See Shrimp/Turtle Appellate Body Report II, supra note 197, para. 133 (confirming that the duty of negotiation requires “serious, good faith efforts”).

²¹⁶ Case Concerning Application of the International Convention on the Elimination of all Forms of Racial Discrimination (Geor./Russ.), Prelim. Objections, 2011 ICJ Rep. 70, 132, para. 157 (Apr. 1).

²¹⁷ Interim Accord Case, 2011 ICJ Rep. at 685, para. 132 (internal citation and quotation marks omitted); see also North Sea Continental Shelf, 1969 ICJ Rep. at 47, para. 85(a) (explaining that the duty to negotiate is a duty “not merely to go through a forma1 process of negotiation,” but rather “an obligation so to conduct themselves that the negotiations are meaningful”).

²¹⁸ German External Debts, 47 ILR at 56, para. 62.

²¹⁹ Id.

²²⁰ See MOX Plant Case, ITLOS No. 10, at para. 9 (Treves, J., separate opinion) (“It may be argued that compliance with procedural rights, relating to cooperation, exchange of information, etc., is relevant for complying with the general obligation of due diligence when engaging in activities which might have an impact on the environment.”).

²²¹ Kuwait v. AMINOIL, 21 ILR 976, 1014, para. 70(i) (1982) (emphasis added); see also Railway Traffic between Lithuania and Poland, Advisory Opinion, 1931, PCIJ, Ser. A/B, No. 42, at 116 (holding that the duty of good faith negotiation is a duty “not only to enter into negotiations, but also to pursue them as far as possible, with a view to concluding agreements”); see also Interim Accord Case, 2011 ICJ Rep. at 685, para. 132 (internal citations omitted) (holding that a state must “pursue [negotiations] as far as possible, with a view to concluding agreements”).

²²² See Chagos, Case No. 2011-03, at para. 528.

²²³ See Pulp Mills, 2010 ICJ Rep. at 68, para. 150 (observing that the duty of good faith negotiation “does not imply an obligation to reach an agreement” (internal citation and quotation marks omitted); Interim Accord Case, 2011 ICJ Rep. at 685, para.132 (same); Shrimp/Turtle Appellate Body Report II, supra note 197, paras. 123, 134 (holding that the United States was not required to conclude a multilateral agreement “in order to avoid ‘arbitrary or unjustifiable discrimination’” because such a requirement would give other WTO members, “in effect, a veto over whether the United States could fulfill its WTO obligations”).

²²⁴ Cf. Tacna-Arica Arbitration (Chile/Peru), 2 RIAA 921, 929 (1925) (observing that where two states have entered an agreement to negotiate a maritime delimitation, neither state is “bound to make an agreement unsatisfactory to itself provided it did not act in bad faith”).

²²⁵ Id. at 930; see also Application of the Interim Accord case (FYROM/Gr.), Judgment, 2011 ICJ Rep. 644, 685, para. 132 (Dec. 5) (endorsing these requirements).

²²⁶ See Interim Accord Case, 2011 ICJ Rep. at 685, para. 132 (emphasizing these considerations); Lake Lanoux Arbitration (Sp./Fr.), Award of 16 Nov. 1957, 12 RIAA 281, para. 11 (same).

²²⁷ See Fisheries-Germany, 1974 ICJ Rep. at 201, para. 65 (emphasizing this factor).

²²⁸ See, e.g., Gabčikovo-Nagymaros Project (Hung./Slovk.), 1997 ICJ Rep. 7, 78, para. 141 (Sept. 25) [hereinafter Gabčikovo-Nagymaros Project]; North Sea Continental Shelf Cases, 1969 ICJ Rep. at 46–47, para. 85.

²²⁹ See UN Charter Art. 33 (providing that when disputes arise that may “endanger the maintenance of international peace and security,” states must, “first of all, seek a solution by negotiation, enquiry, mediation, conciliation, arbitration, judicial settlement, resort to international agencies or arrangements, or other peaceful means of their own choice”).

²³⁰ See Friendly Relations Declaration, supra note 104, at 123 (declaring that “[e]very State shall settle its international disputes with other States by peaceful means,” such as mediation, arbitration, and judicial settlement, and that if these mechanisms fail to broker a solution, “[t]he parties to a dispute have the duty … to continue to seek a settlement of the dispute by other peaceful means agreed upon by them”).

²³¹ See id. (“International disputes shall be settled on the basis of the Sovereign equality of States and in accordance with the Principle of free choice of means.”); Status of Eastern Carelia, 1923 PCIJ (Ser. B) No.5, at 7, 27, para. 33. In practice states may have strong incentives to submit to the compulsory jurisdiction of some tribunals, such as the WTO's Dispute Settlement Body, as a precondition for participation in welfare-enhancing cooperative regimes.

²³² See Kolb, supra note 181, at 195–241 (discussing duties of good faith in international adjudication and arbitration).

²³³ See Hakimi, Monica, The Work of International Law, 58 Harv. Int'l L.J. 1 (2017)Google Scholar.

²³⁴ Gabčikovo-Nagymaros Project, 1997 ICJ Rep. 7.

²³⁵ Id. at 10–17, paras. 1–14.

²³⁶ Id. at 35–36, para. 40.

²³⁷ Id. at 16, para. 13.

²³⁸ Id. at 78, 82, paras. 142, 155(2)(B).

²³⁹ In June 2017, Hungary resumed construction and Slovakia agreed to discontinue proceedings in the ICJ. See Gabčikovo-Nagymaros Project (Hung./Slov.), Press Release (July 21, 2017), available at http://www.icj-cij.org/files/case-related/92/092-20170721-PRE-01-00-EN.pdf [hereinafter Gabčikovo-Nagymaros Press Release].

²⁴⁰ See Friendly Relations Declaration, supra note 104, at 123 (“The parties to a dispute have the duty, in the event of failure to reach a solution by any one of the above peaceful means, to continue to seek a settlement of the dispute by other peaceful means agreed upon by them.”).

²⁴¹ See Shrimp/Turtle Appellate Body Report II, supra note 197, para. 123 (noting that provisional measures are permissible under international law because otherwise “any country party to … negotiations … would have, in effect, a veto over [other states],” which “would not be reasonable”).

²⁴² Cf. Dispute Regarding Navigational and Related Rights, 2009 ICJ Rep. at 252, para. 95 (explaining that a duty to provide notice arises when one state regulates a resource over which another state also has rights).

²⁴³ See Shrimp/Turtle Appellate Body Report II, supra note 197, para. 153(b) (concluding that regulatory standards imposed unilaterally by the United States were permissible on a provisional basis, provided that the parties continued to pursue “ongoing serious good faith efforts to reach a multilateral agreement”).

²⁴⁴ 1 Hugh Thirlway, The Law and Procedure of the International Court of Justice: Fifty Years of Jurisprudence 22 (2013) (observing that good faith presupposes a duty “to preserve the respective rights of either party”); see also Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 2004 ICJ Rep. 136, 184, para. 121 (July 9) (concluding Israel's construction of a wall in the occupied Palestinian territory constituted an impermissible “‘fait accompli’ on the ground that [it] could well become permanent, in which case … it would be tantamount to de facto annexation”).

²⁴⁵ See Delimitation of the Maritime Boundary Case (Guy./Surin.), PCA 2004-04, para. 470 (Sept. 17, 2007) [hereinafter Delimitation of the Maritime Boundary] (“It should not be permissible for a party to a dispute to undertake any unilateral activity that might affect the other party's rights in a permanent manner.”).

²⁴⁶ See Friendly Relations Declaration, supra note 104, at 123 (declaring that in pursuing dispute resolution states must “refrain from any action which may aggravate a [dispute] so as to endanger the maintenance of international peace and security”); South China Sea Arbitration, PCA Case No. 2013-19, at para. 1170 (observing that states bear “a duty to refrain from aggravating or extending a dispute during settlement proceedings,” as recognized “in the widespread inclusion of express provisions to such effect in multilateral conventions providing for the settlement of disputes and its nearly routine inclusion in bilateral arbitration and conciliation treaties”).

²⁴⁷ See North Sea Continental Shelf Cases, 1969 ICJ Rep. at 172, 196 (Tanaka, J., dissenting) (“Reference to the equitable principle is nothing else but begging the question.”).

²⁴⁸ Andrew Guzman, How International Works 50 (2008); see also Fisheries-Iceland, 1974 ICJ Rep. at 141 (Gros, J., dissenting opinion) (dismissing mandatory multilateralism as “devoid of all useful application”).

²⁴⁹ See, e.g., Louis B. Sohn, John E. Noyes, Erik Franckx & Kristen G. Juras, Cases and Materials on the Law of the Sea 79 (2d ed. 2014) (asserting that “due regard” is “so indeterminate that its application by different decision makers will necessarily be unpredictable”).

²⁵⁰ Southern Bluefin Tuna Cases (Austl./Japan; N.Z./Japan), ITLOS Nos. 3 & 4, Provisional Measures 321 (Aug. 27, 1999) (Shearer, J. ad hoc, separate opinion).

²⁵¹ To take one famous example, in the North Sea Continental Shelf Cases, the three parties (Denmark, Germany, and the Netherlands) concluded agreements establishing delimitation lines consistent with equitable balancing that “were more generous to Germany than would have been the case under the equidistance principle.” Jeffrey L. Dunoff, Steven R. Ratner & David Wippman, International Law: Norms, Actors, Process: A Problem-Oriented Approach 595 (4th ed. 2015).

²⁵² See Gabčikovo-Nagymaros Press Release, supra note 239 (noting the parties’ agreement to request dismissal of the proceedings).

²⁵³ See Shrimp/Turtle Appellate Body Report I, supra note 181, paras. 158–60, 168–72 (concluding that certain unilateral regulations imposed by the United States without serious, good-faith negotiations constituted “unjustifiable” and “arbitrary” discrimination under Article XX of GATT 1994).

²⁵⁴ See Okaru-Bisant, Valentina, Institutional and Legal Frameworks of Preventing and Resolving Disputes Concerning the Development and Management of Africa's Shared River Basins, 9 Colo. J. Int'l Envtl. L. & Pol'y 331, 353 (1998)Google Scholar.

²⁵⁵ Lauri Mälksoo, Russia and China Challenge the Western Hegemony in the Interpretation of International Law, EJIL: Talk! (July 15, 2016), at https://www.ejiltalk.org/russia-and-china-challenge-the-western-hegemony-in-the-interpretation-of-international-law (“Outside the West, international law is often portrayed as an hegemonic tool of the West.”).

²⁵⁶ See Alvarez, José A., Hegemonic International Law Revisited, 97 AJIL 873 (2003)CrossRefGoogle Scholar; Vagts, Detlev F., Hegemonic International Law, 95 AJIL 843 (2001)CrossRefGoogle Scholar.

²⁵⁷ Kolb, supra note 181, at 36–37.

²⁵⁸ Katie Hunt, South China Sea: What's at Stake, CNN (Feb. 20, 2017), at https://www.cnn.com/2017/02/19/asia/south-china-sea-explainer/index.html.

²⁵⁹ See, e.g., People's Republic of China, Ministry of Foreign Affairs, Position Paper of the Government of the People's Republic of China on the Matter of Jurisdiction in the South China Sea Arbitration Initiated by the Philippines, para. 4 (Dec. 7, 2014), at www.fmprc.gov.cn/mfa_eng/zxxx_662805/t1217147.shtml.

²⁶⁰ See Tom Phillips, Photos Show Beijing's Militarization of South China Sea in New Detail, Guardian (Feb. 6, 2018), at https://www.theguardian.com/world/2018/feb/06/photos-beijings-militarisation-south-china-sea-philippines; James Griffiths, Duterte Follows Xi's Lead with Military Build-Up in South China Sea, CNN (May 12, 2017), at https://www.cnn.com/2017/05/12/asia/philippines-south-china-sea-pagasa/index.html.

²⁶¹ Reuters, Southeast Asia, China Adopt Framework for Crafting Code on South China Sea, CNBC (Aug. 6. 2017), at https://www.cnbc.com/2017/08/06/asean-china-adopt-framework-for-crafting-code-on-south-china-sea.html.

²⁶² See South China Sea Arbitration, PCA Case No. 2013-19, at 2–3, para. 8. The Philippines also asserted other arguments based on, inter alia, China's construction of artificial islands and its failure to protect the marine environment. Id., para. 9.

²⁶³ See South China Sea Arbitration, PCA Case No. 2013-19, Award on Jurisdiction and Admissibility (Oct. 29, 2015).

²⁶⁴ See South China Sea, Award, at para. 11. Scholars outside China have debated whether the tribunal erred in exercising jurisdiction. Compare Diane Desierto, The Jurisdictional Rubicon: Scrutinizing China's Position Paper on the South China Sea Arbitration—Part I, EJIL: Talk! (Jan. 29, 2015) (defending the tribunal's decision); Diane Desierto, The Jurisdictional Rubicon: Scrutinizing China's Position Paper on the South China Sea Arbitration—Part II, EJIL: Talk! (Jan. 30, 2015) (same); with Julian Ku, Game Changer? Philippines Seeks UNCLOS Arbitration with China Over the South China Sea, Opinio Juris (Jan. 22, 2013) (disputing the tribunal's conclusions on jurisdiction). Chinese scholars have uniformly condemned the tribunal's order on jurisdiction. See Chinese Society of International Law, The South China Sea Arbitration Awards: A Critical Study, 17 Chinese J. Int'l L. 207, 246–397, paras. 48–374 (2018)CrossRefGoogle Scholar [hereinafter CSIL] (unanimously condemning the tribunal's conclusions on jurisdiction).

²⁶⁵ See generally South China Sea, PCA Case No. 2013-19, Award, at 471–77.

²⁶⁶ See Ministry of Foreign Affairs, Statement of the Ministry of Foreign Affairs of the People's Republic of China on the Award of Jurisdiction and Admissibility of the South China Sea Arbitration by the Arbitral Tribunal Established at the Request of the Republic of the Philippines (Oct. 30, 2015), at http://www.fmprc.gov.cn/mfa_eng/zxxx_662805/t1310474.shtml.

²⁶⁷ China Building a New Reef in South China Sea, Think Tank Says, Reuters (Nov. 21, 2018), at https://www.reuters.com/article/us-china-southchinasea/china-building-on-new-reef-in-south-china-sea-think-tank-says-idUSKCN1NQ08Y.

²⁶⁸ James Griffiths, US Calls for Legally Binding Code of Conduct in South China Sea, CNN (Aug. 7, 2017), at https://www.cnn.com/2017/08/07/politics/south-china-sea-us-australia-japan/index.html.

²⁶⁹ See Ben Westcott, Ryan Browne & Zachary Cohen, White House Warns China on Growing Militarization in South China Sea, CNN (May 4, 2018), at https://www.cnn.com/2018/05/03/asia/south-china-sea-missiles-spratly-intl/index.html.

²⁷⁰ See Douglas Guilfoyle, A New Twist in the South China Sea Arbitration: The Chinese Society of International Law's Critical Study, EJIL: Talk! (May 25, 2018) (“The basic problem in putting forward a special Chinese theory or practice of historic rights over an integrated ocean space is that such a theory cannot unilaterally bind other States.”). But see CSIL, supra, note 264, at 450, 454–71, paras. 501, 510–36 (arguing that China's unilateral economic activity and governance establishes “historic rights” within the South China Sea).

²⁷¹ See Guilfoyle, supra note 270 (citing Yoshifumi Tanaka, The International Law of the Sea 58–59 (2d ed. 2015)).

²⁷² See, e.g., South China Sea Arbitration, PCA Case No. 2013–19, at 259–60, paras. 643–46 (concluding that various maritime features claimed by China in the South China Sea are “rocks that cannot sustain human habitation or economic life on their own” and therefore do not qualify for an EEZ or continental shelf under UNCLOS).

²⁷³ Reuters, supra note 261.

²⁷⁴ See, e.g., James Pomfret & Neil Jerome Morales, South China Sea Code of Conduct Talks to Be “Stabilizer” for Region: China Premier, Reuters (Nov. 14, 2017), at https://www.reuters.com/article/us-asean-summit-southchinasea/south-china-sea-code-of-conduct-talks-to-be-stabilizer-for-region-china-premier-idUSKBN1DE05K (noting these criticisms).

²⁷⁵ See South China Sea Arbitration, PCA Case No. 2013-19, at 462, para. 1177 (holding that China violated its obligations under UNCLOS by “effectively creat[ing] a fait accompli at Mischief Reef by constructing a large artificial island on a low-tide elevation located within the Philippines’ exclusive economic zone and continental shelf”). There is arguably a parallel here with Israeli construction of settlements in the West Bank: in both cases, the ascendant power is attempting to create “facts on the ground” that can then be used to justify an assertion of sovereignty over the relevant territory. See Dajani, Omar M., Israel's Creeping Annexation, 111 AJIL Unbound 51 (2017)CrossRefGoogle Scholar.

²⁷⁶ German External Debts, 47 ILR at 56, at para. 62.

²⁷⁷ Id.

²⁷⁸ See Delimitation of the Maritime Boundary, PCA 2004-04, at paras. 470, 480 (concluding that a state may not “undertake any unilateral activity that might affect the other party's rights in a permanent manner,” including “acts that cause a physical change to the marine environment”).

²⁷⁹ See Asia Maritime Transparency Initiative, Update (June 29, 2017), at https://amti.csis.org/chinas-big-three-near-completion (observing that China has continued construction of military and dual-use facilities at Fiery Cross Reef, Mischief Reef, and Subi Reef, while negotiations are ongoing with other ASEAN countries).

²⁸⁰ See Friendly Relations Declaration, supra note 104, at 123 (declaring that states must “refrain from any action which may aggravate a [dispute] so as to endanger the maintenance of international peace and security”).

²⁸¹ See Declaration of the Russian Federation and the People's Republic of China on the Promotion of International Law, para. 2 (June 25, 2016), at http://www.mid.ru/en/foreign_policy/position_word_order/-/asset_publisher/6S4RuXfeYlKr/content/id/2331698.

²⁸² UNFCCC, supra note 23.

²⁸³ Conference of the Parties to the United Nations Framework Convention on Climate Change, Adoption of the Paris Agreement, Annex, Dec. 12, 2015, FCCC/CP/2015/L.9/Rev.1.

²⁸⁴ Paris Agreement, United Nations Treaty Collection, at https://treaties.un.org/Pages/ViewDetails.aspx?src=TREATY&mtdsg_no=XXVII-7-d&chapter=27&lang=_en&clang=_en.

²⁸⁵ Paris Agreement to the United Nations Framework Convention on Climate Change, Art. 2(a), Dec. 13, 2015, in Rep. of the Conference of the Parties on the Twenty-First Session, UN Doc. FCCC/CP/2015/10/Add.1, Annex (2016) [hereinafter Paris Agreement].

²⁸⁶ Id. Art. 2(b).

²⁸⁷ Id. Arts. 3–4.

²⁸⁸ Id. Art. 4, para. 9.

²⁸⁹ Id., at pmbl.

²⁹⁰ Joe Thwaites, Niranjali Manel Amerasinghe & Athena Ballesteros, What Does the Paris Agreement Do for Finance?, World Resources Inst. (Dec. 18, 2015), at https://www.wri.org/blog/2015/12/what-does-paris-agreement-do-finance.

²⁹¹ Criddle & Fox-Decent, supra note 166, at 348–49.

²⁹² UNFCCC, supra note 23, pmbl.; Paris Agreement, supra note 285, pmbl.

²⁹³ See UNFCCC, supra note 23, Art. 3(1).

²⁹⁴ Kyoto Protocol to the United Nations Framework Convention on Climate Change, Art. 3, Dec. 10, 1997, UN Doc FCCC/CP/1997/7/Add.1, 37 I.L.M. 22 (1998).

²⁹⁵ Paris Agreement, supra note 285, Art. 6.

²⁹⁶ Id. Art. 4, para. 4.

²⁹⁷ Id. Art. 13.

²⁹⁸ Id. Art. 14.

²⁹⁹ UNFCCC, supra note 23, Art. 3 para. 1.

³⁰⁰ Paris Agreement, supra note 285, Art. 6.

³⁰¹ Id. Art. 24, referring to UNFCCC, supra note 23, Art. 14.

³⁰² Paris Agreement, supra note 285, Art. 25. Of course, mandatory emission standards established under Kyoto could also be said to reflect sovereign equality (the equality of sovereigns to negotiate and enter treaties) and could be subject to joint stewardship via the UNFCCC Conference of Parties. Organizing principles can explain and justify any number of reasonable policies that fall within their ambit. Our thesis here is that NDCs operate within a multilateral framework that has significant mandatory components, notwithstanding the discretion left to states to craft their own NDCs, and therefore NDCs can be fairly characterized as operating within a regime of mandatory multilateralism that is helpfully explained by sovereign equality and joint stewardship.

³⁰³ Jonathan Easley, Trump Cements “America First” Doctrine with Paris Withdrawal, Hill (June 2, 2017), at http://thehill.com/homenews/administration/336014-trump-cements-america-first-doctrine-with-paris-withdrawal. Multiple polls show that roughly seven out of ten Americans favor remaining in the Paris Agreement. See, e.g., Robinson Meyer, Most Americans Support Staying in the Paris Agreement, Atlantic (May 31, 2017), at https://www.theatlantic.com/science/archive/2017/05/most-americans-support-staying-in-the-paris-agreement/528663.

³⁰⁴ Paris Agreement, supra note 285, Art. 28, paras. 1, 2. The earliest possible effective withdrawal date for the United States is November 4, 2020, a day after the 2020 U.S. presidential election. The United States formally stated its intention to withdraw in an official note to the United Nations delivered on August 4, 2017. See UN Depositary Notification, C.N.464.2017.TREATIES-XXVII.7.d (Aug. 8, 2017).

³⁰⁵ UNFCCC, supra note 23, pmbl.

³⁰⁶ UNCLOS, supra note 24, Art. 125(1). As discussed in Parts II and III, “freedom of the high seas” and the “common heritage of mankind” are predicated on sovereign equality and joint stewardship.

³⁰⁷ Id. Art. 125(3).

³⁰⁸ Id.

³⁰⁹ Id. Art. 125(2). Benvenisti suggests that rights of transit of landlocked states, including those articulated in Article 125 of UNCLOS, can be explained by his “restricted Pareto concept” according to which “one benefits and the other sustains no loss.” Benvenisti, supra note 167, at 322. As Article 125(2) makes clear, however, for the transit rights of landlocked states to be reconciled with the sovereign rights of the transit state, the legally mandated path forward is through good faith, multilateral decision making. And in some contexts, where the passage is relatively lengthy and requires infrastructure such as a railway and port facilities, as is the case with the corridor Chile provides Bolivia, there will necessarily be a cost. If Chile can rightfully refuse to negotiate access to the sea on the basis of this cost, Bolivia's access rights under Article 125 would be illusory.

³¹⁰ See Obligation to Negotiate Access, Memorial of the Government of the Plurinational State of Bolivia, Apr. 17, 2014, Vol. I, at 24–26, paras. 55–59, available at http://www.icj-cij.org/files/case-related/153/153-20140417-WRI-01-00-EN.pdf [hereinafter Bolivia Memorial]

³¹¹ Treaty of Peace and Friendship Between Chile and Bolivia, Oct. 20, 1904, excerpted in Bolivia Memorial, supra note 310, at Vol. II, Annex 100.

³¹² Obligation to Negotiate Access, Application Instituting Proceedings (Apr. 24, 2013), available at http://www.icj-cij.org/files/case-related/153/17338.pdf. The ICJ exercised jurisdiction over the dispute pursuant to Article XXXI of the American Treaty on Pacific Settlement (Pact of Bogota) to which both Bolivia and Chile are members. See Obligation to Negotiate Access, Preliminary Objection, 2015 ICJ Rep. 592, 610, para. 54 (Sept. 24).

³¹³ See Bolivia Memorial, supra note 310, at 125–135, 138–51, 153–54, paras. 304–34, 346–87, 392–96.

³¹⁴ See Obligation to Negotiate Access, Counter-Memorial of the Republic of Chile, Vol. I, at 6–7, para. 1.13(b) (July 13, 2016), available at http://www.icj-cij.org/files/case-related/153/153-20160713-WRI-01-00-EN.pdf [hereinafter Chile Counter-Memorial].

³¹⁵ See Obligation to Negotiate Access, at [31], para. 85.

³¹⁶ As discussed in Part II, states are not entitled under international law to demand that other states relinquish territory. See supra text at note 172.

³¹⁷ See supra Part IV.

³¹⁸ Obligation to Negotiate Access, at 54, para. 175.

³¹⁹ See UNCLOS, supra note 24, Art. 125(2); cf. Obligation To Negotiate Access, at 54, para. 176 (observing that finding a solution to Bolivia's “landlocked situation” is “a matter of mutual interest” for both states).

³²⁰ Chile Counter-Memorial, supra note 314, at 43–45, 53.

³²¹ Id. at 52–54.

³²² Id. at 46.

³²³ Id. at 50–51.

³²⁴ See Gideon Long, Bolivia-Chile Land Dispute Has Deep Roots, BBC News (Apr. 24, 2013), at https://www.bbc.com/news/world-latin-america-22287222 (noting Chile's complaint that Chile had “reneged on agreements to give Bolivia access to ports further south on Chile's long Pacific coastline”).

³²⁵ But see Kishor Uprety, The Transit Regime for Landlocked States: International Law and Development Perspectives 113 (2006) (observing that because bilateral negotiations tend to favor transit states, the resulting agreements “often tend to appear like a generous gesture rather than a provision negotiated by equals,” and arguing that this trend offends “general principles of international law” (i.e., sovereign equality) by making “the status of a country subject to, and conditional upon, the benevolence (or malevolence) of another State” (i.e., domination)).