1 Allott, P., ‘The Concept of International Law’, (1999) 10 EJIL 31CrossRefGoogle Scholar, at 43.

2 This is the case of the most important sources of international law (Art. 38 1945 Statute of the International Court of Justice), i.e., treaties and customary international law. It also applies, however, to general principles, judicial law, and even international organizations’ law to the extent that they rely indirectly on state consent or, at least, on states’ converging practice. See also Klabbers, J., ‘Law-making and Constitutionalism’, in Klabbers, J., Peters, A., and Ulfstein, G. (eds.), The Constitutionalization of International Law (2009), 81, at 100, 114CrossRefGoogle Scholar.

3 From a communitarian perspective of international law, see, e.g., Fitzmaurice, G., ‘The General Principles of International Law Considered from the Standpoint of the Rule of Law’, (1957) 92 Recueil des cours de l'Académie du droit international de La Haye 1, at 36Google Scholar; Pellet, A., ‘The Normative Dilemma: Will and Consent in International Law-Making’, (1989) 12 Australian Yearbook of International Law 22Google Scholar; Simma, B., ‘Consent: Strains in the Treaty System’, in McDonald, R. St.J. and Johnston, D.M. (eds.), The Structure and Process of International Law: Essays in Legal Philosophy, Doctrine and Theory (1983), 485Google Scholar; Tomuschat, C., ‘Obligations arising for states without or against their will’, (1993) 241-IVRecueil des cours de l'Académie du droit international de La Haye 195Google Scholar; Charney, J.L., ‘Universal International Law’, (1993) 87 AJIL 529CrossRefGoogle Scholar. From a value-based perspective of international law, see, e.g., Onuf, N., ‘The Constitution of International Society’, (1994) 5 EJIL 1CrossRefGoogle Scholar; Aleinikoff, T.A., ‘Thinking Outside the Sovereignty Box: Transnational Law and the US Constitution’, (2004) 82 Texas Law Review 1989Google Scholar; Tasioulas, J., ‘The Legitimacy of International Law’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 97Google Scholar; Buchanan, A., ‘The Legitimacy of International Law’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 79Google Scholar; Peters, A., ‘Global Constitutionalism Revisited’, (2005) 11 International Legal Theory 39Google Scholar; Lau, H., ‘Rethinking the Persistent Objector Doctrine in International Human Rights Law’, (2005) 6 Chinese Journal of International Law 495Google Scholar; Dworkin, R., ‘A New Philosophy for International Law’, (2013) 41 Philosophy and Public Affairs 2CrossRefGoogle Scholar. From a rational choice perspective of international law, see, e.g., L.R. Helfer, ‘Nonconsensual International Lawmaking’, (2008) University of Illinois Law Review 71; Guzman, A.T., ‘Against Consent’, (2012) 52 Virginia Journal of International Law 747Google Scholar; Shaffer, G., ‘International Law and Global Public Goods in a Legal Pluralist World’, (2012) 23 EJIL 683CrossRefGoogle Scholar; J.P. Trachtman, The Future of International Law – Global Government (2013).

4 See, e.g., Fitzmaurice, M., ‘Third Parties and the Law of Treaties’, (2002) 6 Max Planck Yearbook of United Nations Law 37CrossRefGoogle Scholar; Fitzmaurice, M., ‘Consent to Be Bound – Anything New under the Sun?’, (2005) 74 Nordic Journal of International Law 483CrossRefGoogle Scholar; Romano, C.P.R., ‘The Shift from the Consensual to the Compulsory Paradigm in International Adjudication: Elements for a Theory of Consent’, (2007) 39 NYU Journal of International Law and Politics 791Google Scholar; J. Pauwelyn, R. Wessel, and J. Wouters (eds.), Informal International Law-Making (2012); Krisch, N., ‘The Decay of Consent: International Law in the Age of Global Public Goods’, (2014) 108 AJIL 1Google Scholar; Pauwelyn, J., Wessel, R., and Wouters, J., ‘When Structures Become Shackles: Stagnation and Dynamics in International Lawmaking’, (2014) 25 EJIL 733CrossRefGoogle Scholar.

5 What is actually meant by the vague notion of ‘being based’ is at the core of this article because accounts vary a lot among international law scholars; some merely refer loosely to consent as a ‘principle’, a ‘meta-norm’, a ‘foundation’ or even an ‘axiom’ of international law (see, e.g., Guzman, supra note 3; Helfer, supra note 3), while others explain what it does and regard it as the basis for either the validity of international law or the international legal obligation and the legitimate authority of international law (see, e.g., J. Crawford, Brownlie's Principles of Public International Law (2012), 20: ‘the general acceptance of states can create rules of general application’; L. Henkin, International Law: Politics and Values (1995), 28: ‘No treaty, old or new, whatever its character, is binding on a state unless it has consented to it’). A similar ambivalence applies to the notion of ‘consent’ that is rarely defined (see infra notes 7 and 28).

6 Because states are the original and sole complete subject of international law and because international law-making is still largely horizontal or decentralized, it is their consent that is at stake in the context of most international law-making to date. I will not, as a result, discuss the issue of the direct participation of other subjects of international law in non-inter-state international law-making in this article. In any case, contra Hollis, D.B., ‘Why Consent Still Matters – Non-State Actors, Treaties and the Changing Sources of International Law’, (2005) 23 Berkeley Journal of International Law 137Google Scholar, I do not think that those subjects’ (esp. democratic) participation in international law-making should be approached through consent. As I will argue in the article, there are distinct democratic grounds for the role of state consent in international law-making: only states can be democratic and enable the accountability of international law to their individual members (at least to date) (see Besson, S., ‘The Authority of International Law – Lifting the State Veil’, (2009) 31 Sydney Law Review 343Google Scholar; Christiano, T., ‘Democratic Legitimacy and International Institutions’ in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 119Google Scholar; Christiano, T., ‘The Legitimacy of International Institutions’, in Marmor, A. (ed.), The Routledge Companion to Philosophy of Law (2012), 380)Google Scholar.

7 Since the early twentieth century, and esp. PCIJ, S.S. Lotus Case (France v. Turkey), Judgment of 7 September 1927, PCIJ Rep Series A No 10, para. 35: ‘The rules of law binding upon states . . . emanate from their own free will.’; ICJ, Barcelona Traction, Light and Power Company, Limited (New Application: 1962) (Belgium v. Spain), Second Phase, Judgment of 5 February 1970, [1970] ICJ Rep. 3, para. 47: ‘Here, as elsewhere, a body of rules could only have developed with the consent of those concerned.’; ICJ, Military and Paramilitary Activities in and Against Nicaragua (Nicaragua v. United States), Merits, Judgment of 27 June 1986, [1986] ICJ Rep. 14, para. 135: ‘In international law there are no rules, other than such rules as may be accepted by the states concerned, by treaty or otherwise.’ For critiques, however, see the individual opinions of judges: e.g., ICJ, Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion of 8 July 1996 (Declaration of President Bedjaoui) [1996] ICJ Rep. 268, at 268–74; Accordance with International Law of the Unilateral Declaration of Independence in Respect of Kosovo, Advisory Opinion of 22 July 2010 (Declaration of Judge Simma), [2010] ICJ Rep. 478, at 479.

8 See, e.g., A.J. Simmons, Moral Principles and Political Obligations (1979); J. Raz, The Morality of Freedom (1986), 88 ff; J. Raz, Ethics in the Public Domain (1995), 80–94; Raz, J., ‘The Problem of Authority: Revisiting the Service Conception’, (2006) 90 Minnesota Law Review 1003, at 1028–9Google Scholar, 1037–40 on consent and the legitimate authority of law.

9 See, e.g., T. Christiano, ‘Democracy’, The Stanford Encyclopedia of Philosophy (Spring 2015 Edition), Edward N. Zalta (ed.), plato.stanford.edu/archives/spr2015/entries/democracy/ on democratic legitimacy, reasonable disagreement and consent. On the notion of ‘reasonable disagreement’ and its implications in legal theory more generally, see S. Besson, The Morality of Conflict – Reasonable Disagreement in the Law (2005), at 91–119.

10 See, e.g., R.A. Falk, The Status of International Law in International Society (1970), 14; G. Binder, Treaty Conflict and Political Contradiction – The Dialectic of Duplicity (1988); Klabbers, supra note 2; Ranganathan, S., ‘Between Philosophy and Anxiety? The Early International Law Commission, Treaty Conflict and the Project of International Law’, (2012) 83 BYIL 82Google Scholar.

11 See, e.g., Klabbers, supra note 2, at 100, 114. See also the numerous textbooks that start by discussing, often critically, consent as ground of international legal obligation, but independently from their conclusion in that first section, then invariably end up presenting and defending a consent-based account of international law-making: see, e.g., Brownlie, supra note 5; A. Clapham, Brierly's Law of Nations – An Introduction to the Role of International Law in International Relations (2012).

12 See, e.g., R. Dworkin, Law's Empire (1986); J. Waldron, Law and Disagreement (1999); Besson, supra note 9.

13 See Besson, supra note 9, at 534–7.

14 See L. Murphy, What Makes Law – An Introduction to the Philosophy of Law (2014), 181.

15 See also Falk, supra note 10, at 178.

16 See even Murphy, supra note 14, at 179 who identifies consent and voluntarism in international law. See also Tasioulas, J., ‘Custom, Jus Cogens and Human Rights’, in Bradley, C. (ed.), Custom's Future: International Law in a Changing World (2016)Google Scholar, forthcoming.

17 See especially, H.J. Morgenthau, Die internationale Rechtspflege, ihr Wesen und ihre Grenzen (1929). See, more generally, A. Orford, ‘Scientific Reason and the Discipline of International Law’, (2014) 25: 2 EJIL 369 on the relationship between international law as a discipline and scientific positivism in the history of international law. See, however, d'Aspremont, J. and Kammerhofer, J., ‘Introduction: the future of international legal positivism’, in Kammerhofer, J. and d'Aspremont, J. (eds.), International Legal Positivism in a Post-Modern World (2014), 1, at 5–6Google Scholar.

18 See also Ranganathan, supra note 10.

19 See, e.g., J. Crawford, Chance, Order, Change: The Course of International Law – General Course on Public International Law (2014).

20 See, e.g., J. Klabbers, The Concept of Treaty in International Law (1996); Binder, supra note 10; Klabbers, J., ‘On Human Rights Treaties, Contractual Conceptions and Reservations’, in Ziemele, I. (ed.), Reservations to Human Rights Treaties and the Vienna Regime: Conflict, Harmony and Reconciliation (2004), 149CrossRefGoogle Scholar; J. Klabbers, Treaty Conflicts and the European Union (2009); Ranganathan, supra note 10.

21 See, e.g., Petersen, N., ‘Customary Law, Consent and the Status Quo Paradox’, in Bradley, C. (ed.), Custom's Future: International Law in a Changing World (2016)Google Scholar, forthcoming; O. Elias, ‘Persistent Objector’, Max Planck Encyclopedia of Public International Law, (2012), Vol. VIII, 280.

22 See, e.g., Klabbers, supra note 2, at 113–14; Klabbers, J., ‘Not Re-Visiting the Concept of Treaty’, in Orakhelashvili, A. and Williams, S. (eds.), 40 Years of the Vienna Convention on the Law of Treaties (2010), 29Google Scholar; Murphy, supra note 14, at 179–82.

23 See, e.g., Tomuschat, supra note 3; Aleinikoff, supra note 3; Peters, supra note 3; Fitzmaurice, ‘Consent’, supra note 4; Romano, supra note 4; Helfer, supra note 3; Clapham, supra note 11, at 50–1.

24 See also Krisch, supra note 4, at 2, 26 ff., 34.

25 See, e.g., Peters, supra note 3; Helfer, supra note 3; Pauwelyn, Wessel, and Wouters, Informal, supra note 4.

26 See the identification at times between ‘consent’ and ‘consensualism’ in Krisch, supra note 4.

27 See also Klabbers, ‘Not Re-Visiting’, supra note 22, at 31 on the concept of ‘treaty’ and its relationship to changes in the factual circumstances of treaty-making.

28 Even in essays devoted to consent in international law such as e.g., Hollis, supra note 6; Helfer, supra note 3; Guzman, supra note 3; Krisch, supra note 4, at. See, however, Fitzmaurice, ‘Consent’, supra note 4, at 484: ‘The role of the procedures of consent to be bound is to constitute a mechanism by virtue of which a treaty becomes binding on states, or, as it was described, acquires characteristics of a “juridical act”.’ See also Hollis, D.B., ‘Defining Treaties’, in Hollis, D.B. (ed.), The Oxford Guide to Treaties (2012), 11, at 19–21CrossRefGoogle Scholar.

29 Since the early twentieth century, and esp. PCIJ, Lotus Case, supra note 7, para. 35: ‘The rules of law binding upon states . . . emanate from their own free will’; ICJ, Nicaragua, supra note 7, para. 135: ‘In international law there are no rules, other than such rules as may be accepted by the states concerned, by treaty or otherwise’; ICJ, Barcelona Traction, supra note 7, para. 47: ‘Here, as elsewhere, a body of rules could only have developed with the consent of those concerned.’

30 For a critique, see Besson, supra note 6, at 358–65; Waldron, J., ‘The Rule of International Law’, (2006) 30 Harvard Journal of Law and Public Policy 15Google Scholar, at 21 ff. See also Venzke, I., ‘Post-modern perspectives on orthodox positivism’, in Kammerhofer, J. and d'Aspremont, J. (eds.), International Legal Positivism in a Post-Modern World (2014), 182, at 187CrossRefGoogle Scholar.

31 See, e.g., Guzman, supra note 3, at 747, 754–5; Helfer, supra note 3; Shaffer, supra note 3; Trachtman, supra note 3.

32 See Mansbridge, et al., ‘The Place of Self-Interest and the Role of Power in Deliberative Democracy’, (2010) 18 The Journal of Political Philosophy 64CrossRefGoogle Scholar.

33 See Besson, supra note 9, at 19–21. See also J. Rawls, Political Liberalism (1993), 389 on consensus as a modus vivendi of different disagreeable positions.

34 See, e.g., Helfer, supra note 3; Krisch, supra note 4.

35 See also Pellet, supra note 3, at 47; Zemanek, K., ‘Majority Rule and Consensus Technique in Law-Making Diplomacy’, in McDonald, R. St.J. and Johnston, D.M. (eds.), The Structure and Process of International Law: Essays in Legal Philosophy, Doctrine and Theory (1983), 857Google Scholar. See, e.g., on European consensus in the ECtHR's case-law: Wildhaber, L., Hjartarson, A., and Donnelly, S., ‘No Consensus on Consensus? The Practice of the European Court on Human Rights’, (2013) 33 Human Rights Law Journal 248Google Scholar. Of course, the search for overlapping consensus is a common technique in international law-making, and so are compromises. As in domestic law, however (see Besson, supra note 9), those techniques are best understood as reactions to persistent reasonable disagreement. And unlike what applies domestically, moreover, agreement remains central to international law-making, hence this article's paradox in the first place.

36 See, e.g., Tasioulas, supra note 16, on opinio juris qua “consensus” as opposed to “consent”.

37 See also Korontzis, G., ‘Making the Treaty’, in Hollis, D.B. (ed.), The Oxford Guide to Treaties (2012), 177, at 184Google Scholar.

38 Curiously, there is no mention of mutuality in Arts. 2 and 11 VCLT and the term only appears in passing and much later in the VCLT.

39 See Fitzmaurice, ‘Consent’, supra note 4, at 484–5; A. Aust, Modern Treaty Law and Practice (2013), Ch. 2–3; Gautier, P., ‘Article 2’, in Corten, O. and Klein, P. (eds.), The Vienna Conventions on the Law of Treaties (2011), 33Google Scholar; Korontzis, supra note 37; Hollis, ‘Defining’, supra note 28, at 676–85.

40 See, e.g., Hollis, ‘Defining’, supra note 28, at 19–21; Klabbers, The Concept of Treaty, supra note 20, at 40, 51; Aust, supra note 39, at 12; M. Fitzmaurice and O. Elias, Contemporary Issues in the Law of Treaties (2005), 6–25.

41 See, e.g., Hollis, ‘Defining’, supra note 28, at 25–8; Klabbers, The Concept of Treaty, supra note 20, at 40, 51; Aust, supra note 39, at 12; Fitzmaurice and Elias, supra note 40, at 6–25.

42 This explains why states parties cannot decide that a treaty, once concluded, will not be binding (e.g., qua ‘Memorandum of understanding’). See also Klabbers, The Concept of Treaty, supra note 20, at 212–16, 249 and Klabbers, ‘Not Re-Visiting’, supra note 22, at 29 (in reply to Aust, supra note 39, Ch. 3); Klabbers, J., ‘The Validity and Invalidity of Treaties’, in Hollis, D.B. (ed.), The Oxford Guide to Treaties (2012), 551Google Scholar.

43 See, e.g., in the context of human rights treaties, Higgins, R., ‘Human Rights: Some Questions of Integrity’, (1989) 15 Commonwealth Law Bulletin 598CrossRefGoogle Scholar; Craven, M., ‘Legal Differentiation and the Concept of the Human Rights Treaty in International Law’, (2000) 11 EJIL 489CrossRefGoogle Scholar; Besson, S., ‘The Sources of International Human Rights Law’, in Besson, S. and d'Aspremont, J. (eds.), The Oxford Handbook on the Sources of International Law (2017)Google Scholar, forthcoming. See also Hollis, ‘Defining’, supra note 28, at 38–9.

44 The VCLT itself also refers to ‘contracting’ states before they become parties to the treaty (Art. 2(1)(f)). This is common to all regimes of international law.

45 See also Besson, supra note 6, at 346–8.

46 H.L.A. Hart, The Concept of Law (1994), 226–8. See also Murphy, supra note 14, at 179; Dworkin, supra note 3, at 9–10; Klabbers, supra note 2, at 113.

47 Hart, supra note 46, at 220–1. See also Klabbers, supra note 2, at 113.

48 Murphy, supra note 14, at 149.

49 To that extent, Hart arguably had a potential answer, albeit within the realm of international law, to Dworkin 1986’s ‘semantic sting’ and ‘theoretical disagreement’ critique to the rule of recognition. For a co-ordination-based account of the rule of recognition that combines (i) the existence of a moral duty to co-ordinate with (ii) the minimal requirement of converging practice instead of full agreement and hence a reply to Dworkin, more generally, see Besson, supra note 9, at 161–203. Of course, things are slightly more complicated for the rule of recognition in international law because of the conflation between states qua officials and states qua subjects and hence between the internal and external points of view.

50 Hart, supra note 46, at 235–6. See Murphy, supra note 14, at 146.

51 See Murphy, supra note 14, at 147 ff.; Payandeh, M., ‘The Concept of International Law in the Jurisprudence of H.L.A. Hart’, (2011) 21 EJIL 967CrossRefGoogle Scholar, at 982–5; Besson, S., ‘Theorizing the Sources of International Law’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 163Google Scholar.

52 See Raz, Morality, supra note 8, at 88 ff.; Raz, Ethics, supra note 8, at 80–94; Raz, ‘The Problem of Authority’, supra note 8, at 1028–9, 1037–40. See also Buchanan, supra note 3.

53 See, more generally, Simmons, supra note 8.

54 See Buchanan, supra note 3; Lister, M., ‘The Legitimating Role of Consent in International Law’, (2010) 11 Chicago Journal of International Law 663Google Scholar.

55 See Raz, Morality, supra note 8, at 89; Raz, Ethics, supra note 8, at 355–69; Raz, ‘The Problem of Authority’, supra note 8, at 1028–9, 1037–40.

56 See Besson, supra note 6, at 352, 371–2; Raz, Morality, supra note 8, at 90, 93; Raz, Ethics, supra note 8, at 368–9.

57 See for an explanation of the conflation, Hershovitz, S., ‘Legitimacy, Democracy and Razian Authority’, (2003) 9 Legal Theory 201CrossRefGoogle Scholar.

58 See Christiano, supra note 9. See also Hershowitz, supra note 57, at 215; Besson, supra note 6, at 354.

59 See Christiano, supra note 9.

60 See Christiano, supra note 9.

61 See Christiano, supra note 9.

62 See also Besson, supra note 9, at 91–119.

63 See Peters, A., ‘Dual Democracy’, in Klabbers, J., Peters, A., and Ulfstein, G. (eds.), The Constitutionalization of International Law (2009), 289Google Scholar; Besson, supra note 6, at 354.

64 See Christiano, ‘Democratic Legitimacy’, supra note 6; Christiano, ‘Legitimacy of International Institutions’, supra note 6.

65 See Buchanan, A. and Keohane, R., ‘The Legitimacy of Global Governance Institutions’, (2006) 20 Ethics and International Affairs 405Google Scholar.

66 See Besson, supra note 6, at 371; Raz, Ethics, supra note 8, at 360 ff.; Raz, ‘The Problem of Authority’, supra note 8, at 1037 ff.

67 See, e.g., Guzman, supra note 3, at 752–3; Helfer, supra note 3, at 73.

68 See, e.g., Pellet, supra note 3, at 37; Gaja, G., ‘Discussion’, in Cassese, A. and Weiler, J.H.H. (eds.), Change and Stability in International Law-Making (1988), 16Google Scholar, at 16.

69 See actually Guzman, supra note 3; Helfer, supra note 3, at 73.

70 See S. Besson, ‘International Legality – A Reply to Shapiro & Hathaway’, Online symposium, (2011) Opinio Juris, opiniojuris.org/2011/11/13/opinio-jurisyale-law-journal-symposium-hathaway-and-shapiro-on-outcasting/ in reply to Hathaway, O. and Shapiro, S.J., ‘Outcasting: Enforcement in Domestic and International Law’, (2011) 121 The Yale Law Journal 252Google Scholar.

71 See Besson, supra note 6, at 351 ff.

72 See Besson, supra note 6, at 352 ff.; Besson, supra note 51. See also Dworkin, supra note 3, at 19 ff. for a similar salience-based account of the legitimate authority of international law.

73 See also Murphy, supra note 14, at 179.

74 See, e.g., Brierly, J.L., ‘The Lotus Case’, in Lauterpacht, H. and Waldock, C.H.M. (eds.), The Basis of Obligation in International Law and Other Papers by the Late James Leslie Brierly (1958), 142Google Scholar, at 143–4; Clapham, supra note 11; Guzman, Against Consent, supra note 3; Dworkin, New Philosophy, supra note 3, at 5, 8. For a discussion of the straw-man of positivist voluntarism in international law, see d'Aspremont and Kammerhofer, supra note 17, at 5, d'Aspremont, J., ‘Herbert Hart in today's international legal scholarship’, in Kammerhofer, J. and d'Aspremont, J. (eds.), International Legal Positivism in a Post-Modern World (2014), 114CrossRefGoogle Scholar, at 144–6.

75 See Murphy, supra note 14, at 179–80; D.J. Bederman, Custom as a Source of Law (2010), 138–40.

76 H. Grotius, De iure belli ac pacis, lib. I, Prolegomena, nn. 16–17.

77 See, e.g., G. Anschütz, Drei Leitgedanken der Weimarer Reichsverfassung (1923).

78 See also Collins, R., ‘Classical legal positivism in international law revisited’, in Kammerhofer, J. and d'Aspremont, J. (eds.), International Legal Positivism in a Post-Modern World (2014), 23CrossRefGoogle Scholar.

79 See, e.g., J.L. Goldsmith and E.A. Posner, The Limits of International Law (2005); A.T. Guzman, How International Law Works – A Rational Choice Theory (2008).

80 See, e.g., d'Aspremont, supra note 74, at 144–6.

81 See Klabbers, J., ‘Clinching the Concept of Sovereignty: Wimbledon Redux’, (1998) 3 Austrian Review of International and European Law 345CrossRefGoogle Scholar.

82 PCIJ, S.S. Wimbledon, Judgment of 17 August 1923, PCIJ Rep Series A No 01, para. 25.

83 PCIJ, Lotus Case, supra note 7, para. 35. For a critique, see Pellet, A., ‘Lotus que de sottises on profère en ton nom! Remarques sur le concept de souveraineté dans la jurisprudence de la Cour mondiale’, in Belliard, E.et al. (eds.), L'Etat souverain dans le monde d'aujourd'hui – Mélanges en l'honneur de Jean-Pierre Puissochet (2008), 215Google Scholar.

84 Endicott, T., ‘The Logic of Freedom and Power’, in Besson, S. and Tasioulas, J. (eds.), The Philosophy of International Law (2010), 245Google Scholar. See also Besson, supra note 6, at 373; Besson, S., ‘Sovereignty’ in Wolfrum, R. (ed.), The Max Planck Encyclopedia of Public International Law, vol IX (2012)Google Scholar.

85 See Hart, supra note 46, at 223.

86 See also Besson, ‘Sovereignty’, supra note 84; Besson, supra note 6, at 372–4.

87 Raz, Ethics, supra note 8, at 365–6; Raz, ‘The Problem of Authority’, supra note 8, at 1014.

88 See also Murphy, supra note 14, at 179.

89 For a general discussion of those different options, see Besson, S., ‘Ubi Ius, Ibi Civitas. A Republican Account of the International Community’, in Besson, S. & Martí, J.L. (eds.), Legal Republicanism and Republican Law – National and Post-National Perspectives (2009), 204CrossRefGoogle Scholar.

90 See Besson, supra note 6, at 368–70.

91 See also Christiano, ‘Democratic Legitimacy’, supra note 6.

92 See Besson, S., ‘Human Rights and Democracy in a Global Context – Decoupling and Recoupling’, (2011) 4 Ethics and Global Politics 19Google Scholar.

93 T. Christiano, ‘The legitimacy of international environmental institutions’, in J. Moss (ed.), Climate Change and Justice (2015).

94 See also Besson, supra note 6, at 368–70.

95 See Besson, supra note 6, at 369–70; Besson, S., ‘Sovereignty, International Law and Democracy – A Reply to Waldron’, (2011) 22 EJIL 373CrossRefGoogle Scholar in reply to Waldron, J., ‘Are Sovereigns Entitled to the Benefit of the International Rule of Law?’, (2011) 22 EJIL 315CrossRefGoogle Scholar; Christiano, ‘Democratic Legitimacy’, supra note 6.

96 See, e.g., Klabbers, supra note 2, at 114; Benvenisti, E. and Downs, G.W., ‘The Empire's New Clothes: Political Economy and the Fragmentation of International Law’, (2007–2008) 60 Stanford Law Review 595Google Scholar; E. Benvenisti and G.W. Downs, ‘Comment on Nico Krisch’, 26 March 2014, www.asil.org/blogs/comment-nico-krisch-%E2%80%9C-decay-consent-international-law-age-global-public-goods%E2%80%9D, in reply to Krisch, supra note 4.

97 Christiano, supra note 93. See also Klabbers, J., ‘International legal positivism and constitutionalism’, in Kammerhofer, J. andd'Aspremont, J. (eds.), International Legal Positivism in a Post-Modern World (2014), 264CrossRefGoogle Scholar, at 285 albeit from a constitutionalist perspective.

98 See also Christiano, supra note 93.

99 See on these standards, Buchanan, A., ‘Reciprocal Legitimation: Reframing the Problem of International Legitimacy’, (2011) 10 Politics, Philosophy & Economics 5Google Scholar, at 15–16; A. Buchanan, Justice, Legitimacy and Self-determination: Moral Foundations for International Law (2004), at 187–9.

100 See Besson, supra note 6, at 349–50 on the different justifications for the authority of domestic and international law.

101 See also Christiano, supra note 93.

102 See also Besson, ‘Sovereignty’, supra note 84; Besson, supra note 6, at 372–4.

103 The justification of the exception of democratic state consent is sovereign equality and not merely equal sovereignty.

104 Exceptions to legitimate authority should not be conflated with exclusions or exemptions from it (as in the case of justified exceptionalism e.g.). On the distinction, see Besson, supra note 6, at 374 ff.

105 See, e.g., Besson, S., ‘Subsidiarity in International Human Rights Law – What is Subsidiary about Human Rights?’, in Barber, N., Ekins, R., and Yowell, P. (eds.), Subsidiarity (2016)Google Scholar, forthcoming.

106 See Klabbers, supra note 2, at 111 ff.; Klabbers, supra note 97, at 285 ff.

107 See PCIJ, Lotus Case, supra note 7, para. 35.

108 See, e.g., Crawford, supra note 19, 247; M. Wood, Special Rapporteur, Third Report on identification of customary law, 27 March 2015, UN Doc. A/CN.4/682, para. 94. See also Hollis, ‘Defining’, supra note 28, at 28 on yet another presumption: the ‘being a treaty’ presumption unless a clear intent to the contrary is stated.

109 See Klabbers, supra note 2, at 122; Klabbers, ‘Validity’, supra note 42, at 554.

110 Consent is not necessary to co-ordinate, however. See also Besson, supra note 6, at 353; Besson, supra note 9, at 473–5; Waldron, supra note 12, at 25–7.

111 See also Pellet, supra note 3, at 45 on the evidentiary advantages of consent.

112 See also Besson, supra note 6, at 371–2.

113 See Christiano, supra note 93.

114 See Besson, supra note 6, at 345–6, 370–2; Raz, ‘The Problem of Authority’, supra note 8, at 1028–9.

115 See Christiano, ‘Legitimacy of International Institutions’, supra note 6 and 2014; Klabbers, ‘Validity’, supra note 42, at 570–4.

116 This is a common critique to state consent (e.g., C.R. Beitz, Political Theory and International Relations (1999); F.R. Teson, A Philosophy of International Law (1998)), but it is misplaced, however. See, e.g., Human Rights Committee, Mr Rawle Kennedy v. Trinidad and Tobago, Communication No. 845/1998, 28 March 2002, UN Doc. CCPR/C/74/D/845/1998.

117 See Kamminga, M.T., ‘State Succession in Respect of Human Rights Treaties’, (1996) 7 EJIL 46CrossRefGoogle Scholar.

118 See Bederman, D.J., ‘Third Party Rights and Obligations in Treaties’, in Hollis, D. (ed.), Oxford Guide to Treaties (2014), 328, at 341–5Google Scholar.

119 See Christiano, supra note 93. See also Pauwelyn, Wessel and Wouters, ‘Structures’, supra note 4 on the additional requirements placed on state consent under WTO law.

120 Of course, there is a well-known difficulty in the idea of the freedom of the will: it can only be free (vis-à-vis law) if constrained (by law) in order to be free. See also Koskenniemi, M., ‘The Politics of International Law’, (1990) 1 EJIL 1CrossRefGoogle Scholar on this tension with respect to state consent.

121 See, e.g., Klabbers, ‘Validity’, supra note 42.

122 See Kingsbury, B., ‘The Concept of “Law” in Global Administrative Law’, (2009) 20 EJIL 23CrossRefGoogle Scholar; Murphy, supra note 14, at 164 ff.; Krisch, supra note 4.

123 See Christiano, ‘Democracy’, supra note 9.

124 See Christiano, supra note 93.

125 See Helfer, supra note 3, at 73–4; Guzman, supra note 3; Shaffer, supra note 3; Trachtman, supra note 3; Krisch, supra note 4, at 3, 6.

126 See Besson, supra note 9, at 161 ff., 459 ff., 503 ff.; Besson, supra note 6, at 352–3, 367 for a full argument; Waldron, J., ‘Authority for Officials’, in Meyer, L.H., Paulson, S.L. and Pogge, T.W. (eds.), Rights, Culture and the Law: Themes from the legal and political philosophy of Joseph Raz (2003), 45CrossRefGoogle Scholar, at 49. Contra: Kumm, M., ‘The Cosmopolitan Turn in Constitutionalism: On the Relationship Between Constitutionalism in and Beyond the State’, in Dunoff, J.L. and Trachtman, J.P. (eds.), Ruling the World? International Law, Global Governance, Constitutionalism (2009), 258, at 298CrossRefGoogle Scholar.

127 This is a common critique to state consent (e.g., Charney, supra note 3; Tomuschat, supra note 3; Simma, B., ‘From Bilateralism to Community Interests in International Law’, (1994) 250 Recueil des cours de l'Académie de droit international 217)Google Scholar, but it is misplaced, however.

128 See for various proposals, Christiano, supra note 93.

129 See, e.g., Klabbers, The Concept of Treaty, supra note 20; Binder, supra note 10; Klabbers, ‘On Human Rights’, supra note 20; Klabbers, Treaty Conflicts, supra note 20; Ranganathan, supra note 10.

130 See, e.g., Aust, supra note 39, Ch. 8.

131 See Human Rights Committee, General Comment No. 24 on issues relating to reservations made upon ratification or accession to the Covenant or the Optional Protocols thereto, or in relation to declarations under Art. 41 of the Covenant, 11 November 1994, UN Doc. CCPR/C/21/Rev.1/Add.6, para. 18.

132 See, e.g., Goodman, R., ‘Human Rights Treaties, Invalid Reservations and state Consent’, (2002) 96 AJIL 531CrossRefGoogle Scholar; Craven, supra note 43, at 495–7; Redgwell, C.J., ‘Reservations to Treaties and Human Rights Committee General Comment No 24 (52)’, (1997) 46 International & Comparative Law Quarterly 390CrossRefGoogle Scholar; Higgins, supra note 43.

133 See also Klabbers, ‘On Human Rights’, supra note 20, albeit for other reasons.

134 See, e.g., Gardiner, R., ‘The Vienna Convention Rules on Treaty Interpretation’, in Hollis, D.B. (ed.), The Oxford Guide to Treaties (2012), 475–506Google Scholar.

135 Klabbers, ‘On Human Rights’, supra note 20, at 181.

136 See, e.g., the Study Group of the International Law Commission, ‘Fragmentation of International Law: Difficulties arising from the Diversification and Expansion of International Law’, 13 April 2006, UN Doc. A/CN.4/L.682.

137 See Klabbers, Treaty Conflicts, supra note 20, at 90; Ranganathan, supra note 10, at 87 ff.

138 See Ranganathan, supra note 10, at 91.

139 See also Allott, supra note 1, at 39.

140 See, e.g., Petersen, supra note 21; Klabbers, Treaty Conflicts, supra note 20, at 113 ff.; Crawford, supra note 19, 247; M. Byers, Custom, Power and the Power of Rules – International Relations and Customary International Law (1999), 142–6; Weil, P., ‘Towards Relative Normativity in International Law’, (1983) 77 AJIL 413CrossRefGoogle Scholar, at 433–4.

141 This consent-based understanding of persistent objections in the formation of customary international law has been confirmed in Wood, Third Report, supra note 108, at 61–9. Contra: Tasioulas, supra note 16; Guzman, supra note 3, at 775 ff.; Dumberry, P., ‘Incoherent and Ineffective: The Concept of Persistent Objector Revisited’, (2010) 59 International and Comparative Law Quarterly 779Google Scholar; Lau, supra note 3.