¹ Voluntarism, as employed here, refers to approaches that distinguish law from not-law with reference to the presence or absence of state consent to be bound. It is closely associated with Lassa Oppenheim and Heinrich Triepel. For a discussion of Oppenheim's conception of international law's validity, see Kingsbury, B., ‘Legal Positivism as Normative Politics: International Society, Balance of Power and Lassa Oppenheim's Positive International Law’, (2002) 13 EJIL 401CrossRefGoogle Scholar. For a discussion of Triepel's positivism and of the emergence of a positivist account of international law more generally, see Hall, S., ‘The Persistent Spectre: Natural Law, International Order and the Limits of Legal Positivism’, (2001) 12 EJIL 269CrossRefGoogle Scholar.

² Formalism, as the term is employed here, refers to approaches that distinguish law from not-law with reference to the means with which putative rules come into existence. A legal rule is such if it is adopted by the appropriate authority and according to the prescribed procedure, as defined by secondary rules contained within the legal system. It is most closely associated with Hans Kelsen: see M. Koskenniemi, ‘Formalism, Fragmentation, Freedom: Kantian Themes in Today's International Law’, (2007) 4 No Foundations 7; Hall, supra note 1; Kammerhofer, J., ‘Kelsen – Which Kelsen? A Reapplication of the Pure Theory to International Law’, (2009) 22 LJIL 225CrossRefGoogle Scholar. This approach appears almost identical to voluntarism, since the (formal) rules of recognition of international law can be interpreted as requiring state consent in one form or another. A central difference between formalists and voluntarists is that the latter read the rules of recognition as requiring state consent. The source ‘general principles of international law’, though acceptable on a formalist reading, encounters problems from the point of view of voluntarism, as it is difficult to see how these principles can be grounded in state consent. Similarly, the voluntarist approach to customary law requires reference to legal fictions such as implicit acceptance, or acceptance by newly independent states of the existing body of international rules as a condition of statehood.

³ See also Christine Chinkin's categorization: instruments that ‘have been articulated in non-binding form according to traditional modes of law-making’; that ‘contain vague and imprecise terms’; that ‘emanate from bodies lacking international law-making authority’; that ‘are directed at non-state actors whose practice cannot constitute customary international law’; that ‘lack any corresponding theory of responsibility’; or that ‘are based solely upon voluntary adherence, or rely upon non-juridical means of enforcement’: Chinkin, C., ‘Normative Development in the International Legal System’, in Shelton, D. (ed.), Commitment and Compliance: The Role of Non-Binding Norms in the International System (2000), 21Google Scholar, at 30.

⁴ Boyle, A., ‘Some Reflections on the Relationship of Treaties and Soft Law’, (1999) 48 ICLQ 901CrossRefGoogle Scholar, at 250–1.

⁵ C. Chinkin, ‘The Challenge of Soft Law: Development and Change in International Law’, (1989) ICLQ 850; Baxter, R., ‘International Law in “Her Infinite Variety”’, (1980) 29 ICLQ 549CrossRefGoogle Scholar; Gruchalla-Wesierski, T., ‘A Framework for Understanding “Soft Law”’, (1984–85) 30 McGill Law Journal 37Google Scholar; Dupuy, R., ‘Declaratory Law and Programmatory Law: From Revolutionary Custom to “Soft Law”’, in Akkerman, R. (ed.), Declarations of Principles: A Quest for Universal Peace (1977), 252Google Scholar; Thürer, D., ‘Soft Law – eine neue Form von Völkerrecht?’, (1985) 104 Zeitschrift für schweizerisches Recht 429Google Scholar.

⁶ Hillgenberg, H., ‘A Fresh Look at Soft Law’, (1999) 10 EJIL 499CrossRefGoogle Scholar, at 500; I. Seidl-Hohenveldern, International Economic Law (1999), 39; Carlson, J., ‘International Law and World Hunger: Hunger, Agricultural Trade Liberalization, and Soft International Law: Addressing the Legal Dimensions of a Political Problem’, (1985) 70 Iowa Law Review 1187Google Scholar, at 1200; Inglese, C., ‘Soft Law?’, (1993) 20 Pol. YIL 75Google Scholar; Klabbers, J., ‘The Redundancy of Soft Law’, (1996) 65 Nordic Journal of International Law 167CrossRefGoogle Scholar. Klabbers would exclude commitments of a political or moral character, including only ‘instruments which are to be considered as giving rise to legal effects, but do not (or not yet, perhaps) amount to real law’, at 168.

⁷ Abi-Saab, G., ‘Cours général de droit international public’, (1987) 207 RCADI 9Google Scholar; I. Duplessis, ‘Le vertige de la soft law: Réactions doctrinales en droit international’, (2007) Revue québecoise de droit international 246; Kirton, J. and Trebilcock, M., ‘Introduction: Hard Choices and Soft Law in Sustainable Global Governance’, in Kirton, J. and Trebilcock, M. (eds.), Hard Choices, Soft Law: Voluntary Standards in Global Trade, Environment and Social Governance (2004), 3Google Scholar. Mary Footer does not refer to norms promulgated by non-state actors but does include, in her definition of soft law, norms promulgated by international organizations: Footer, M., ‘The (Re) Turn to “Soft Law” in Reconciling the Antinomies in WTO Law’, (2010) 11 Melb. JIL 241Google Scholar, at 246–7.

⁸ d'Aspremont, J., ‘Softness in International Law: A Self-Serving Quest for New Legal Materials’, (2008) 19 EJIL 1075CrossRefGoogle Scholar; Carlson, supra note 6, at 1203; Seidl-Hohenveldern, supra note 6; W. Heusel, ‘Weiches’ Völkerrecht: eine vergleichende Untersuchung typischer Erscheinungsformen (1991).

⁹ I use the term reluctantly here, as my own approach to normativity is much broader. I would argue, for example, that definitions of aggression or torture, or secondary rules regarding rule creation, are normative even if they do not create rights or obligations. Nevertheless, the term will be used here for the sake of convenience.

¹⁰ Abi-Saab, supra note 7; Dupuy, P., ‘Soft Law and the International Law of the Environment’, (1990) 12 Mich. JIL 420Google Scholar.

¹¹ D'Amato, A., ‘Softness in International Law: A Self-Serving Quest for New Legal Materials: A Reply to Jean d'Aspremont’, (2009) 20 EJIL 897CrossRefGoogle Scholar; Abbott, K. et al., ‘The Concept of Legalization’, (2000) 54 IO 401Google Scholar.

¹² Onuf, N., ‘Do Rules Say What They Do? From Ordinary Language to International Law’, (1985) 26 Harv. JIL 385Google Scholar, at 399–402.

¹³ For legal pluralists, this does not pose a problem, but the authors considered here are not legal pluralists.

¹⁴ Gunther Teubner is highly critical of a functional approach to law, arguing that one cannot identify law's singular function and that a different approach to distinguishing it from other normative and social systems should be taken: Teubner, G., ‘“Global Bukowina”: Legal Pluralism in the World Society’, in Teubner, G. (ed.), Global Law without a State (1997), 3Google Scholar, at 13–14.

¹⁵ D'Amato, supra note 11, at 899, despite D'Amato's assertion that he goes on to treat soft law as norms that are not legally binding, at least in international law; see also Baxter, supra note 5; Abbott, K. and Snidal, D., ‘Hard and Soft Law in International Governance’, (2000) 54 IO 421Google Scholar.

¹⁶ D'Amato, supra note 11, at 902.

¹⁷ Ibid., at 902.

¹⁸ Koskenniemi, supra note 2, at 18; d'Aspremont, J., ‘The Politics of Deformalization in International Law’, (2011) 3 Göttingen Journal of International Law 503Google Scholar, at 539.

¹⁹ D'Aspremont, supra note 8, at 1085 ff.; d'Aspremont's approach, focusing on the distinction between a legal fact and a legal act, is not adopted here, but it does permit him to make this point neatly: the negotium, or the expression of the authors’ intentions (in other words, the content of the rule), may be ‘soft’ in the sense of creating no clear obligations, or no obligations whatsoever, but the rule's validity as a rule of law depends not on that, but rather on the instrumentum, or the container for the rule's content: d'Aspremont, supra note 18, at 1081.

²⁰ But see Ago, R., ‘Positive Law and International Law’, (1957) 51 AJIL 691CrossRefGoogle Scholar.

²¹ Baxter, supra note 5; d'Aspremont, supra note 8. This is one of three definitions of soft law explored by Boyle, supra note 4, at 906 ff.

²² Quebec Civil Code, Art. 1457.

²³ See Baxter, supra note 5, at 561.

²⁴ Weil, P., ‘Towards Relative Normativity in International Law?’, (1983) 77 AJIL 413CrossRefGoogle Scholar, at 414–15.

²⁵ Ibid., at 414; see also Inglese, supra note 6, at 81–2.

²⁶ Klabbers, J., ‘Constitutionalism and the Making of International Law: Fuller's Procedural Natural Law’, (2008) 5 No Foundations 84Google Scholar, at 84.

²⁷ Ibid., at 84; J. d'Aspremont, Formalism and the Sources of International Law (2011), at 149.

²⁸ D'Aspremont, supra note 27, at 65–8.

²⁹ The authors’ approaches are nevertheless different. Klabbers, relying on Hart's analysis of internal and external elements of law, proposes a presumption of legality: ‘normative utterances should be presumed to give rise to law, unless and until the opposite can somehow be proven.’ The normative utterance alone is not sufficient; one must also consider ‘how norms are received by their possible addressees’: J. Klabbers, A. Peters, and G. Ulfstein, The Constitutionalization of International Law (2009), at 115, 119; Klabbers, supra note 26, at 90; d'Aspremont argues that intent, to lead to the formation of law, must be expressed in a particular form, ‘by a systematic use of written linguistic indicators’: d'Aspremont, supra note 27, at 185 (emphasis in original).

³⁰ Dupuy, supra note 10; Chinkin, supra note 3, at 30–1; Carlson, supra note 6, at 1202 ff.; Gold, J., ‘Strengthening the Soft International Law of Exchange Arrangements’, (1983) 77 AJIL 443CrossRefGoogle Scholar, at 443; Abi-Saab, supra note 7, at 209 ff.; Footer, supra note 7.

³¹ For a Kantian interpretation of the distinction between the articulation and application of a rule, see Koskenniemi, supra note 2, at 9–10.

³² Carlson, supra note 6, at 1204 ff.

³³ It could be argued that this concern is misplaced, as the parties to the dispute will have agreed to grant jurisdiction to the adjudicatory body. Yet the parties may make unwarranted predictions about the manner in which the adjudicators will interpret and apply vague provisions, and may be in for some unpleasant surprises. Furthermore, the interpretation will, despite the fact that there is, formally, no doctrine of precedent in international law, have impacts on other parties to the convention subject to interpretation.

³⁴ D'Amato, supra note 11; Chinkin, supra note 5.

³⁵ Koskenniemi, supra note 2; Koskenniemi, M., ‘Constitutionalism as Mindset: Reflections on Kantian Themes about International Law and Globalization’, (2007) 8 Theoretical Inquiries in Law 9Google Scholar; Klabbers, J., ‘The Undesirability of Soft Law’, (1998) 67 Nordic Journal of International Law 381CrossRefGoogle Scholar; Chinkin, supra note 5.

³⁶ Footer, supra note 7, at 248; Shelton, D., ‘Soft Law’, in Armstrong, D. (ed.), Routledge Handbook of International Law (2009), 68Google Scholar.

³⁷ Palmer, G., ‘New Ways to Make International Environmental Law’, (1992) 86 AJIL 259CrossRefGoogle Scholar, at 270.

³⁸ Klabbers, J., ‘Informal Agreements in International Law: Towards a Theoretical Framework’, (1994) 5 Finnish Yearbook of International Law 267Google Scholar, at 361–2; Klabbers, Peters, and Ulfstein, supra note 29, at 89.

³⁹ Chinkin, supra note 3, at 29.

⁴⁰ Boyle, supra note 4; Finnemore, M. and Sikkink, K., ‘International Norm Dynamics and Political Change’, (1998) 52 IO 887Google Scholar. Finnemore and Sikkink do not focus on legal norms; nevertheless, their discussion of the life cycle of international norms, at 895 ff., is highly illuminating for discussions of the emergence of international legal norms.

⁴¹ This is one of the insights of the interactional-law approach, drawing on Lon Fuller's conception of the internal morality of law, taken by J. Brunnée and S. Toope, Legitimacy and Legality in International Law: An Interactional Account (2010).

⁴² Ibid., at 98 ff.

⁴³ D'Aspremont, supra note 27, at 129 (footnotes omitted, emphasis in original).

⁴⁴ This could refer to the perceived need to include non-state actors in law-making processes (Duplessis, supra note 7, at 250–1) or to the unequal influence of different groups of states on law-making processes (Seidl-Hohenveldern, supra note 6, at 40).

⁴⁵ Kirton and Trebilcock, ‘Introduction’, supra note 7; Chinkin, supra note 3, at 22.

⁴⁶ See, e.g., Palmer, supra note 37, at 269.

⁴⁷ Weil, supra note 24, at 418–19.

⁴⁸ Ibid., at 420–1.

⁴⁹ Ibid., at 421.

⁵⁰ Klabbers, supra note 35, at 391.

⁵¹ Di Robilant, A., ‘Genealogies of Soft Law’, (2006) 54 American Journal of Comparative Law 499CrossRefGoogle Scholar, at 508.

⁵² H. Arendt, The Human Condition (1958), at 198.

⁵³ Klabbers, J., ‘Possible Islands of Predictability: The Legal Thought of Hannah Arendt’, (2007) 20 LJIL 1CrossRefGoogle Scholar, at 8.

⁵⁴ Arendt, supra note 52, at 9, 177–8.

⁵⁵ Ibid., at 41.

⁵⁶ Ibid., at 190 ff., 232 ff.

⁵⁷ Ibid., at 237.

⁵⁸ Klabbers, supra note 53, at 9–11.

⁵⁹ Ibid., at 9; Klabbers refers to Arendt, supra note 52, at 244.

⁶⁰ Klabbers, supra note 53, at 38.

⁶¹ J. Habermas, Between Facts and Norms: Contributions to a Discourse Theory of Law and Democracy (translated by W. Rehg) (1998), 38.

⁶² Kingsbury, B., ‘International Law as Inter-Public Law’, in Richardson, H. and Williams, M. (eds.), Nomos XLIX: Moral Universalism and Pluralism (2009), 181Google Scholar.

⁶³ Hall, supra note 1.

⁶⁴ Kingsbury, supra note 1, at 416.

⁶⁵ Ibid., at 436.

⁶⁶ See, e.g., Klabbers, supra note 6; Klabbers, supra note 35; Klabbers, Peters, and Ulfstein, supra note 29.

⁶⁷ Klabbers, Peters, and Ulfstein, supra note 29.

⁶⁸ L. Fuller, The Morality of Law (1964), 107.

⁶⁹ Ibid., at 63, 145.

⁷⁰ Ibid., at 106.

⁷¹ Ibid., at 91.

⁷² Postema, G., ‘Implicit Law’, in Witteveen, W. and van der Burg, W. (eds.), Rediscovering Fuller: Essays on Implicit Law and Institutional Design (1999), 255Google Scholar, at 255, 260.

⁷³ Ibid., at 262 (emphasis in original).

⁷⁴ Hart has given extensive consideration to the problem of interpretation of legal rules. He argues that legal rules have an ‘open texture’, the consequence of which is that, at some point, rules will prove indeterminate: H. L. A. Hart, The Concept of Law (1997), 124. This indeterminacy, in Hart's conception, appears around the edges of the scope of a rule's application – rules possess a ‘core of settled meaning’ surrounded by a ‘penumbra’ of uncertainty: H. Hart, Essays in Jurisprudence and Philosophy (1983), 63. The approach taken here differs in that the rule's ‘core of settled meaning’ is not regarded as an inherent quality of the rule itself, but rather as the result of a shared understanding regarding the meaning of the rule and the scope of its application. At one point in time, it may seem beyond dispute that a rule will receive a particular interpretation: for example, it once appeared self-evident that state sovereignty implied a right of the sovereign to define and pursue domestic policy goals without interference from other states. This interpretation of sovereignty remains highly persuasive and pervasive, but has lost its self-evidence. The content of the ‘core of settled meaning’ will change and evolve with changes in the shared understandings surrounding the rule.

⁷⁵ Brunnée and Toope, supra note 41, at 6.

⁷⁶ Ibid., at 29, 42 ff.; Klabbers, Peters, and Ulfstein, supra note 29, at 100.

⁷⁷ Brunnée and Toope, supra note 41, at 65 ff.

⁷⁸ Ibid., at 51.

⁷⁹ Brunnée and Toope open their book with a discussion of protests against the Iraq war, and refer to comments made by one protester, an 11-year-old boy in Los Angeles, questioning the evidence upon which the decision to go to war had ostensibly been based: ibid., at 1–2.

⁸⁰ Ibid., at 46.

⁸¹ Klabbers, Peters, and Ulfstein, supra note 29; Klabbers, supra note 26.

⁸² Klabbers, Peters, and Ulfstein, supra note 29, at 113.

⁸³ Ibid., at 115.

⁸⁴ Kingsbury, B., ‘The Concept of “Law” in Global Administrative Law’, (2009) 20 EJIL 23CrossRefGoogle Scholar, at 31 (footnotes omitted).

⁸⁵ Ibid.

⁸⁶ Ibid., at 30.

⁸⁷ Ibid., at 32–3.

⁸⁸ Ibid., at 30.

⁸⁹ Kingsbury, supra note 62, at 168.

⁹⁰ Ibid.

⁹¹ Ibid., at 168–9.

⁹² Ibid., at 188.

⁹³ Ibid., at 168, 188.

⁹⁴ Ibid., at 170.

⁹⁵ Ibid., at 171; see also Koskenniemi, M., ‘The Future of Statehood’, (1992) 32 Harv. JIL 397Google Scholar.

⁹⁶ Kingsbury, supra note 62, at 173.

⁹⁷ Kingsbury, supra note 1, at 436.

⁹⁸ Kingsbury, supra note 62, at 196.

⁹⁹ Kingsbury, supra note 84, at 56.

¹⁰⁰ Kuo, M., ‘The Concept of “Law” in Global Administrative Law: A Reply to Benedict Kingsbury’, (2010) 20 EJIL 997CrossRefGoogle Scholar, at 1003.

¹⁰¹ One promising approach is that of Karl-Heinz Ladeur: his approach is based not on direct democracy, but on global society conceived of as a network of networks in which individuals either do or could participate: K. Ladeur, Globalisation and the Conversion of Democracy to Polycentric Networks: Can Democracy Survive the End of the Nation State? (2003).

¹⁰² Somek, A., ‘The Concept of “Law” in Global Administrative Law: A Reply to Benedict Kingsbury’, (2010) 20 EJIL 985CrossRefGoogle Scholar, at 986–7.

¹⁰³ Ibid., at 988.

¹⁰⁴ Kingsbury, supra note 84, at 34, referring to D. Dyzenhaus, ‘The Concept of (Global) Administrative Law’, (2009) Acta Juridica.

¹⁰⁵ Kingsbury, supra note 84, at 25–6.

¹⁰⁶ Ibid., particularly at 29 ff.; see also Kingsbury, supra note 62.

¹⁰⁷ Somek, supra note 102, at 990.

¹⁰⁸ Kingsbury, supra note 84, at 24.

¹⁰⁹ Ibid., at 41.

¹¹⁰ Ibid., at 23.

¹¹¹ King and Thornhill note the difficulties of translating Recht/Unrecht, which encompasses both legal/illegal and lawful/unlawful, into English, where both pairs of concepts are needed. Recht/Unrecht permits the legal system to determine whether an actor is in the right (the question the legal system tends to ask in a private-law context) or in the wrong (a question better suited for criminal law). But it also permits the legal system to distinguish itself from its environment: certain aspects of a factual situation will be relevant for law and others will not; certain aspects will be relevant for law generally but not for a given legal dispute: M. King and C. Thornhill, Niklas Luhmann's Theory of Politics and Law (2006), 55.

¹¹² Teubner, supra note 14, at 12.

¹¹³ Ibid., at 4.

¹¹⁴ Ibid.

¹¹⁵ Ibid., at 15.

¹¹⁶ Ibid., at 16.

¹¹⁷ Ibid.

¹¹⁸ Ibid.

¹¹⁹ Ibid., at 16–19.

¹²⁰ Ibid., at 19 (emphasis added).

¹²¹ Teubner, G., ‘Breaking Frames: Economic Globalization and the Emergence of Lex Mercatoria’, (2002) 5 European Journal of Social Theory 199CrossRefGoogle Scholar, at 159.

¹²² Arendt, supra note 52.

¹²³ Cashore, B., ‘Legitimacy and the Privatization of Environmental Governance: How Non-State Market-Driven (NSMD) Governance Systems Gain Rule-Making Authority’, (2002) 15 Governance 503CrossRefGoogle Scholar; Cashore, B., Auld, G., and Newsom, D., ‘Forest Certification (Eco-Labeling) Programs and Their Policy-Making Authority: Explaining Divergence among North American and European Case Studies’, (2003) 5 Forest Policy and Economics 225CrossRefGoogle Scholar; B. Cashore, G. Auld, and D. Newsom, Governing through Markets: Forest Certification and the Emergence of Non-State Authority (2004).

¹²⁴ The FSC's mission is ‘to promote environmentally appropriate, socially beneficial and economically viable management of the world's forests’; Forest Stewardship Council, ‘About – Who We Are – Vision’, available at www.fsc.org/vision_mission.html.

¹²⁵ Forest Stewardship Council, ‘About – Who We Are – Governance’, available at www.fsc.org/membership_chambers.html. The three chambers are Environmental, Social, and Economic; each is further divided into North and South.

¹²⁶ Teubner, G., ‘Societal Constitutionalism: Alternatives to State-Centred Constitutional Theory?’, in Joerges, C., Sand, I., and Teubner, G. (eds.), Transnational Governance and Constitutionalism (2004), 3Google Scholar, at 21, 25–6. The need for the autonomy of law is clearly underlined in the discussion of lex mercatoria in Teubner, supra note 14.

¹²⁷ D'Aspremont, supra note 27, at 129.