Selected problems in the theory of customary international law

Netherlands International Law Review

Volumn 50, Issue 2, 2003, Pages 119-150

  Kolb, Robert ^a  

^a UNIVERSITY OF BERN   (Switzerland)

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EID: 84941920744     PISSN: 0165070X     EISSN: 17416191     Source Type: Journal    
DOI: 10.1017/S0165070X03001190     Document Type: Article

References (76)

1. See Art. 38(1)(b) of the Statute of the ICJ, which reads as follows: 'The Court. shall apply:. international custom, as evidence of a general practice accepted as law.’ In the case-law of the ICJ, see North Sea Continental Shelf Cases, ICJ Rep. (1969) p. 44, para. 77; Continental Shelf (Libya/Malta), ICJ Rep. (1985) pp. 29 – 30, para. 27; Military and Paramilitary Activities in and Against Nicaragua, ICJ Rep. (1986) p. 97, para. 183; Legality of the Threat or Use of Nuclear Weapons, ICJ Rep. (1996–1) p. 253, para. 64. According to th & Dictionnaire de droit international public published under the lead of J. Salmon, custom may be defined as: 'La coutume est le resultat de la conjonction d’unepratique effective et de l ’acceptation par les Etats du caractere juridique - et done obligatoire - des conduites constitutives d’une telle pratique.’’ (Dictionnaire de droit international public (Brussels, Bruylant2001) p. 284).
2. Cf., R. Jennings and A. Watts, eds., Oppenheim 's International Law, Vol. 1, 9th edn. (London, Longman 1992) p. 26. To this, the practice of other subjects of international law may be added, e.g., that of international organisations. See M. Mendelson, 'The Formation of Customary International Law’, 272 RCADI( 1998) pp. 198 et seq.
3. See P. Malanczuk, Qd., Akehurst's Modern Introduction to International Law, 7th edn. (London, Routledge 1997) p. 44. According to the ICJ, in the often-quoted passage of the North Sea cases: 'Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is rendered obligatory by the existence of a rule of law requiring it. The need for such a belief, i.e., the existence of a subjective element, is implicit in the very notion ofdm the opinio juris sive necessitatis. The states concerned must therefore feel that they are conforming to what amounts to a legal obligation. The frequency, or even habitual character of the acts is not in itself enough. There are many international acts, e.g., in the field of ceremonial and protocol, which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty’ (Human Rights in the World n. 2, at p. 44, para. 77). 5. As was admirably said by Ch. De Visscher, in his Theories et realites en droit international public, 2nd edn. (Paris, Pedone 1955) p. 190: 'Les incertitudes qui subsist ent ausujet de la formation coutumiere concernent surtout le processus mental par lequel Vesprit humain associe la normativite (idee de Vobligation) a certaines regularites sociales. Le lien qui, apres coup, s ’etablit ici ne peut etre precise en termes generaux. C ’est que I’idee d’ordre qui, surcepoint, guide lapenseejuridique, procede elle-meme d’une representation de valeurs, de certains imperatifs moraux et sociaux qui, dans les rapports internationaux surtout, n ’ont rien d’immuable. Ni les donnees de fait a utiliser (nombre, specificite), ni la direction dans laquelle ces donnees s ’ enchaineront pour prendre un jourforme etfigure de “ precedents ” constitutifs de la coutume ne sauraient etre l ’objet de generalisations dans une theorie de la coutumel Or, in the sppbwords of R.J. Dupuy: '[D]ans la coutume classique, la multiplication defaits produit une croissance de la conscience juridique, selon un processus existentiel dans lequel Texistence precede Tessence, qualifiee apres coup par le droit. ’ ('Communaute internationale et disparites de developpement’, 165 RCADI (1979-1V) p. 171).
4. One might also say that this school reads the convergence of opinio iuris required by the mainstream as evidencing the existence of a tacit agreement. This view was generally sustained by the positivistic and voluntarist stream of international lawyers. See, e.g., D. Anzilotti, Corso di diritto internazionale (Rome, Atheneum 1928) pp. 63 et seq., 68; S. Seferiades, 'AperQus sur la coutume juridique internationale et notamment sur son fondement’, 43 RGDIP (1936) pp. 131 – 132, 135, 145. On this school of thought, see H. Gunther, Zur Entstehung von Volkergewohnheitsrecht (Berlin, Duncker & Humblot 1970) pp. 22 et seq.; G. Gianni, La coutume en droit international (Paris, Pedone 1931) pp. 59 et seq.; A. Verdross, 'Entstehungsweisen und Geltungsgrund des universellen volkerrechtlichen Gewohnheitsrechts’, 29 ZaoRV (1969) pp. 636 - 637; M.H. Mendelson, 'The Subjective Element in Customary International Law’, 66 BYIL (1995) pp. 184 et seq.; P. Ziccardi, 'La consuetudine inter-nazionale nella teoria delle fonti giuridiche’, 10 Comunicazioni e studi (1958/59) pp. 191 et seq.; J. Kunz, 'The Nature of Customary International Law’, 47 AJIL (1953) pp. 663 – 664. See also P. Haggenmacher, 'La doctrine des deux elements du droit coutumier dans la pratique de la Cour internationale’, 90 RGDIP (1986) pp. 13 - 15; R. Walden, 'The Subjective Element in the Formation of Customary International Law’, 12 Israel L Rev. (1977) pp. 350 et seq. See also the materials quoted in R. Kolb, La bonne foi en droit international public (Paris, Presses Universitaires de France 2000) p. 316.
5. See, e.g., Mendelson, Human Rights in the World n. 3, at pp. 289 et seq.: widespread practice suffices, opinio iuris does only serve in some cases in order to exclude acts which are clearly meant to stay outside the realm of law, e.g., acts of courtesy (opinio non iuris). See also H. Kelsen, 'Theorie du droit international coutumier’, 1 Revue internationale de la theorie du droit, nouvelle serie (1939) pp. 264 et seq.; P. Guggenheim, Traite de droit international public, Vol. 1 (Geneva, Georg 1953) pp. 46 et seq.
6. This can be claimed in several ways, e.g., that if there is a constant practice opinio iuris may be presumed unless the contrary is proven: see Seferiades, Human Rights in the World n. 6, atp. 144; M. Sorensen, 'Principes de droit international public’, 101 RCADI (1960-III) p. 51; Diss. op. Azevedo, Asylum case, ICJRep. (1950) p. 336. Another way of reaching the same result is to claim that practice and opinio iuris are indissolubly intertwined in the same acts, statements and behaviours, which form the basis of customary law. See also Haggenmacher, Human Rights in the World n. 6, atpp. 108 etseq., pp. 113 - 114: 'L ’etablissementd’une norme coutumiere ne se reduit pas a verifier objectivement la realisation du pseudo-processus de formation suggere par la doctrine classique et a en constaterpassivement le resultat: le juge ne se borne pas a cueillir un fruit muri sur I’arbre de la pratique au soleil de/'opinio juris. Son role est au contraire createur, quasi-legislatif, etil demande a etre saisi comme tel. S’inscrivant dans la dynamique concrete de la procedure, telle que la fagonnent lesparties, il implique une perspective specifique: ily a toujours saisie glob ale et retrospective d’un ensemble complexe de donnees, a la lumiere d’une norme disputee, a propos d’un litige concret. C’est I’objet concret du differend qui commande en definitive toute la demarche. Jamais celle-ci ne consistera en une reconstruction historique, lineaire et detachee, du pretenduprocessus q ui aurait condu it a l ’emergencede la norm e. C ’est a contre-courant que l ’interprete cherche a saisir la coutume. Sa demarche ne reproduit en rien celle des acteurs censes avoir engendre la regie. Leurs actes poursuivaient des fins concretes, mais n ’ entendaient guere promouvoir des normes et des principes. C’est I’interprete, apres coup, qui en degage cette composante insoupgonnee des acteurs; et il le fait en fonctiond’un probleme present qui, tel un eclair age inattendu, imprime aux faits epars du passe une signification nouvelled
7. The authors associated with these schools of thought are in the vein of the tradition established by the historical school of law of the 19th century. See, e.g., R. Ago, Scienza giuridica e diritto internazionale (Milan, Giuffre 1950) pp. 78 et seq.
8. According to this view, customary law emerges as an ever-changing aggregate of claims, couter-claims and decisions, which shape a web of shared expectations about the course of conduct which is expected. For some authors this mechanism is of a prevalently empirical nature, i.e., the expectation which becomes the basis of the customary rule is seen as a fact: see, e.g., the New Haven school, M. McDougal, 'International Law, Power and Policy: A Contemporary Conception’, 82 RC4D/(1953-I) pp. 137 et seq.; M. Reisman, 'International Law-Making: A Process of Communication’, ASIL Proceedings (1981) pp. 101 et seq. For other authors, the mechanism is of a more normative nature. It is based on the idea of 'legitimate expectations’ according to what could and should be expected by the States Parties to the interaction in good faith: see, e.g., J.P. Muller, Vertrauensschutz im Volkerrecht (Cologne, Carl Heymans Verlag 1971)pp.77 etseq.; Gunther, Human Rights in the World n. 6, atpp. 138etseq.; Mendelson, Human Rights in the World n. 3, at pp. 184–186, 188, 292.
9. E.g., A. d’Amato, The Concept of Custom in International Law (Ithaca, Cornell University Press 1971).
10. This new custom is handler's as a means of legislation, mainly through resolutions of international organs accepted so widely that it becomes possible to claim that the resolution expresses the will of the international community. This 'wild custom’ is used consciously with the aim of producing law within an integrated and institutionalised framework (especially that of the United Nations) and is often formulated in a general and abstact way. In the words of R.-J. Dupuy, essence here precedes existence, contrary to classical customary law, where the rule emerged out of a multiplicity of disparate acts and facts. On this new custom, see among others R.-J. Dupuy, 'Coutume sage et coutume sauvage’, in Melanges C. Rousseau (Paris, Pedone 1974) pp. 75 et seq.; G. Abi-Saab, 'La coutume dans tous ses Etats ou le dilemme du developpementdu droit international general dansun monde eclate’, in Melanges R. Ago, Vol. 1 (Milan, Giuffre 1987) pp. 53 etseq.
11. It has thus been said that recent developments show that practice relies more and more on the subjective element to the detriment of the objective one, postulating that a norm arises out of some statements or some constructive collective commitments gathered out of soft law texts instead of concrete acts of state practice. See, e.g., P. Weil, 'Le droit international en quete de son identite: cours general de droit international public’, 237 RCADI (1992-VI) pp. 173 et seq. at p. 173: 'La doctrine en a frequemment fait Vobservation: depuis quelques annees/’opinio juris tend a prendre le pas sur la pratique, celle-ci n ’etantplus appelee qu’a confirmer V opinio juris si tant estqu ’elle n ’en dispense pas completement. L ’evolution n ’estcertespas monolithique, car des arrets recents continuent a se referer a la pratique; la minimisation de la pratique n’en est pas moins indeniabled The famous conception of 'instant custom’ is equally based on the - in this case extreme - prevalence of the subjective element over the objective one. The basis for discussion of instant custom is the celebrated article of B. Cheng, 'United Nations Resolutions on Outer Space: Instant International Customary Law?’, 5 Indian JIL (1965) pp. 23 et seq.
12. Thus, e.g., with the growth of international fora allowing an expression of collective will, (abstract) statements have been incorporated into the elements of practice and of opinio iuris, thus widening the empire of custom. Cf., M. Akehurst, 'Custom as a Source of International Law’, 47 BYIL (1974/5) pp. 1 et seq.
13. See, e. g,. the reflections of G. Sperduti, La fonte suprema dell’ordinamento internazionale (Milan, Giuffre 1946) pp. 155 et seq. 16. See P. Ziccardi, La costituzione dell’ordinamento internazionale (Milan, Giuffre 1943) pp. 161 et sulmeq.
14. On this conceptthe literature is abundant: see, e.g., B. Simma, 'From Bilateralism to Community Interest in International Law’, 250 RCADI (1994-VI) pp. 229 et seq.; J.A. Carrillo Salcedo, 'Droit international et souverainete des Etats, cours general de droit international public’, 257 RCADI (1996) pp. 132 et seq.; C. Tomuschat, 'International Law: Ensuring the Survival of Mankind in the Eve of a New Century’, 281 RCADI (1999) pp. 77 et seq. On the concept of 'international public order’, see G. Jaenicke, 'International Public Order’, in Encyclopedia of Public International Law (hereinafter: EPIL), Vol. 3(E-I) (Amsterdam, North-Holland 1995) pp. 1348–1351.
15. One often mentions, e.g., the norms on the prohibition of aggression or the fundamental human rights (including the prohibition of genocide, crimes against humanity or grave breaches of international humanitarian law).
16. See the doctrine quoted in R. Kolb, Theorie du ius cogens international (Paris, Presses Uni-versitaires de France 2001) pp. 68 et seq., pp. 124 et seq.
17. See, e.g., Tomuschat, Human Rights in the World n. 17, atp. 334; R. Abi-Saab, 'Les conflits internes aujourd’hui’, in Melanges J. Siotis (Bruxelles, Bruylant 1995) pp. 323–325. 21. As to some extent suggested by Weil, Human Rights in the World n. 13, at pp. 175–176.
18. See G. Abi-Saab, 'L’eloge du “droit assourdi” - Quelques reflexions sur le role de la soft law en droit international contemporain’, in Nouveaux itineraires en droit, Essays in Honoyr of F. Rigaux (Bruxelles, Bruylant 1993) pp. 59 et seq. In this sense, international is 'hungry of norms’.
19. See also K. Zemanek, 'The Legal Foundations of the International System - General Course on Public International Law’, 266 RCAD I (1997) pp. 165–167.
20. On the state of the jurisprudence after the Nuremberg, Tokyo and follow-up trials, see United Nations War Crimes Commission, ed., Law Reports of Trials of War Criminals, Vols. I-XV (London, HMSO 1946–1949).
21. Thus it has been said that sovereign equality is an axiomatic assumption of international law which was inherited by the modern inter-state system and neither created conventionally nor created through practice. Cf,. L. Henkin, 'General Course of Public International Law. International Law: Politics, Values and Functions’, 216 RCADI (9%9-W) pp. 45 et seq.
22. See C. Tomuschat, 'Obligations Arising for States Without or Against their Will’, 241 RCADI (1993-IV) pp. 292 et seq. 27. For a strong and eloquent argument against the deductive method in international law, which he equates with law-making in disguise, see G. Schwarzenberger, The Inductive Approach to International Law (London, Stevens and Sons 1965); idem, 'The Fundamental Principles of International Law’, 87 RCADI(1955 – 1) pp. 200 et seq.;idem, International Law - As Applied by International Courts and Tribunals, Vol. I (London, Stevens and Sons 1957) pp. 4 et seq.; idem, A Manual of International Law, 5th edn. (London, Stevens and Sons 1967) pp. 21 et seq.
23. With respect to nuclear weapons, see also the strictly deductive reasoning of H. Mosler: any means which negates the survival of mankind and the very existence of the international legal community must be considered unlawful under international law: H. Mosler; 'Volkerrecht als Rechtsordnung’, 36 ZaoRV (1976) p. 44. Cf. also, G. Dahm, Volkerrecht, Vol. 1 (Stuttgart, Kohlhammer 1958) p. 39.
24. See Tomuschat, Human Rights in the World n. 1763, at pp. 355–357. According to this author, some basic moral considerations are directly applicable as law, e.g., through the 'elementary considerations of humanity’ as expressed in the Corfu Channel case. This means that obligations may arise for states directly from the 'constitution of the international community’ in which certain core values are entrenched, in particular peace, human life and dignity. According to Tomuschat, the United Nations Charter and the Declaration of Human Rights of 1948 may also serve as a basis for such reasoning.
25. Tomuschat here quotes the International Court, whose Chamber stated in the Gulf of Maine case (1984): '[Customary law] in fact comprises a limited set of norms for ensuring the co-existence and vital co-operation of the members of the international community, together with a set of customary rules whose presence in the opinio juris of States can be tested by induction based on the analysis of a sufficiently extensive and convincing practice, and not by deduction from preconceived ideas’ (ICJRep. (1984) p. 299). The Chamber seems to enunciate the existence of two types of custom, one rooted in the very structure of the international community (constitutional custom) and another rooted in the actual practice of states (administrative custom). But the sentence can also be read otherwise, specifically in the sense that in the first category practice and opinio iuris are already settled, whereas in some new areas (for example, the law of maritime delimitation, with which the Chamber was dealing) one must see to what extent an opinion on the law is confirmed by actual practice. 31. This happens relatively frequently. See, e.g., B. Conforti, Diritto internazionale, 4th edn. (Naples, Editoriale Scientifica 1992)pp.42 etseq.;idem, 'Cours general de droit international public’, 212 RCADI (1988-V) pp. 77 et seq.
26. As does the Statute of the International Court of Justice, Art. 38(1)(c).
27. As for pacta, see, e.g., Henkin, quoted in footnote 25. As for good faith, see, e.g., Tomuschat, quoted in footnote 26, p. 322; H. Mosler, 'General Principles of Law’,EPIL, Vol. 7 (1984) p. 91; and even Schwarzenberger 1955, Human Rights in the World n. 27, at pp. 325–326.
28. See, e.g., Kolb, Human Rights in the World n. 6, at pp. 41–42. 35. On this notion, see Dahm, Human Rights in the World n. 28, atp. 17; F.A. von der Heydte, 'Glossen zu einer Theorie der allgemeinen Rechtsgrundsatze’, 33 Die Friedenswarte (1933) pp. 296–297.
29. See on this point Mendelson, Human Rights in the World n. 3, atpp. 198 et seq.; Kolb, Human Rights in the World n. 6, at pp. 37–38, with many quotations.
30. This is sometimes done by the International Court of Justice, e.g., in the Passage through the Great Belt case (Psydloxflrovisional Measures), ICJ Rep. (1991) p. 20, where the Court invites the parties to negotiate. See also the Qatar v. Bahrein cas e, ICJRep. (1994)p. 125, para. 38. The old Central American Court of Justice, which existed from 1908 to 1918, frequently took a diplomatic, as opposed to judicial, approach, a fact which contributed to its ultimately being discredited. See N. Politis, La justice international (Paris, Hachette 1924) pp. 139 et seq. 38. Thus, the ICJ gave preference to opinio iuris over practice by looking, e.g., to the text of Resolutions of the General Assembly of the United Nations: Military and Paramilitary Activities in and Against Nicaragua, ICJ Rep. (1986) pp. 99 - 100, para. 188: 'The Court thus finds that both Parties take the view that the principles as to the use of force incorporated in the United Nations Charter correspond, in essentials, to those found in customary international law. The Parties thus both take the view that the fundamental principle in this area is expressed in the terms employed in Article 2, paragraph 4, of the United Nations Charter. They therefore accept a treaty-law obligation to refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any other manner inconsistent with the purposes of the United Nations. The Court has however to be satisfied that there exists in customary international law an opinio iuris as to the binding character of such abstention. This opinio iuris may, though with all due caution, be deduced from, inter alia, the attitude of the Parties and the attitude of States towards certain General Assembly resolutions, and particularly resolution 2625 (XXV) entitled “ Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations ”. The effect of consent to the text of such resolutions cannot be understood as merely chat of a “reiteration or elucidation” of the treaty commitment undertaken in the Charter. On the contrary, it may be understood as an acceptance of the validity of the rule or set of rules declared by the resolution by themselves. The principle of non-use of force, for example, must thus be regarded as a principle of customary international law, not as such conditioned by provisions relating to collective security.’ See also the Threat or Use of Nuclear Weapons Opinion, ICJ Rep. (1996) p. 255, paras. 70 – 73. On the approach of the Court in the Nicaragua case, see H. Charlesworth, 'Customary International Law and the Nicaragua Case’, 11 Australian YIL (1984–7) pp. 1 et seq.; J.I. Charney, 'Customary International Law in the Nicaragua Case, Judgment on the Merits’, 1 Hague YIL (1988) pp. 16 et seq.; W. Czaplinski, 'Sources of International Law in the Nicaragua Case’, 38 ICLQ (1989) pp. 151 et seq.; A. d’Amato, 'Trashing Customary International Law’, 81 AJIL (1987) pp. 101 et seq.; M.H. Mendelson, 'The Nicaragua Case and Customary Law’, in W. Butler, ed., The Non-Use of Force in International Law (Dordrecht, Nijhoff 1989) pp. 85 et seq.; P.P. Rijpkema, 'Customary International Law in the Nicaragua Case’, 20 NYIL (1989) pp. 91 et seq.
31. In re Piracy Jure Gentium[1934] AC 588. According to Schwarzenberger 1965, Human Rights in the World n. 27, at p. 35 custom is a 'superstructure of a comparative analysis of State practice’.
32. In other words: in nature, the gap between the 'is’ and the 'ought’ is infinite. It can be bridged only by an intellectual effort of man. 41. As to this concept of analogy (or hermeneutics), see among others A. Kaufmann, Analogie und Natur des Sache: Zugleich ein Beitrag zur Lehre vom Typus, 2nd edn. (Heidelberg, Decker & Muller 1982); idem, Rechtsphilosophie, 2nd edn. (Munich, Beck 1997) pp. 78 et seq., 83 et seq.
33. The same problem exists in the establishment of the general principles of law defined by Art. 38(1)(c) of the Statute of the ICJ. See Kolb, Human Rights in the World n. 6, at p. 53: 'La solution de la question de savoir si un principe est commun aux divers ordres juridiques depend du degre d’abstraction sur lequel on choisit a priori de se placer. La demarche a de quoi troubler. On se doute que le choix de ce niveau dependra le plus souvent d’un prejuge favorable ou defavorable a Vexistence d’un principe commun regissant la matiere a examiner. Plus un operateur se placera sur un plan abstrait et plus une regie pourra se reveler “ generate tout ce qui monte converge a-t-on dit avec raison. Plus l ’operateur sera concret, et plus il sera confronte aux reglementations particulieres auxquelles est soumis un principe qu ’il risque fort de ne plus considerer sujfisamment “general ”. Iln’ya guere de regies liant l ’interprete dans le choix du niveau d’abstraction.’ 43. See on this point the criticisms ofZemanek, Human Rights in the World n. 23, atpp. 75 et seq.
34. See D. Bardonnet, 'La largeur de la mer territoriale’, 66 RGDIP (1962) pp. 34 et seq. 45. Ch. De Visscher, Human Rights in the World n. 5, atpp. 190–191.
35. See, e.g., the short statements by I. Brownlie, Principles of Public international's Law, 4th edn. (Oxford, Clarendon Press 1990) pp. 5–6.
36. ICJ (1969) p. 43, para. 74. See also Akehurst, Human Rights in the World n. 14, at p. 15. 48. See on this point Mendelson, Human Rights in the World n. 3, at pp. 170 et seq.
37. On these points see the explanations of Akehurst, Human Rights in the World n. 14, at pp. 12 et seq.
38. Cf., Malanczuk, Human Rights in the World n. 4, at p. 42.
39. See, e.g., Diss.op. Tanaka, South West Africa cases, ICJRep. (1966) p. 291; Sep. op. Ammoun, North Sea Continental Shelf cases, ICJ Rep. (1969) p. 130.
40. Akehurst, Human Rights in the World n. 14, at p. 18: 'The number of States needed to create a rule of customary law varies according to the amount of practice which conflicts with the rule. A practice followed by a very small number of States can create a rule of customary law if there is no practice which conflicts with the rule.’ 55. Oppenheim Human Rights in the World n. 3, atp. 30.
41. See also, e.g., Mendelson, Human Rights in the World n. 3, at pp. 217–218. 57. Sorensen, Human Rights in the World n. 8, at p. 50. Or, in the words of N. Bobbio, La consuetudine come fatto normativo (Padova, CEDAM 1942) pp. 53 - 54: 'Ilche viene a dire [tramite la dottrina dell opinio iuris/, a parole tutte spiegate, che la norma consuetudinaria persuppone per il suo formarsi la convinzione, in chi l ’osserva, che una norma giuridicapreesista. II circolo vizioso e evidente: da un lato si considera/’opinio come elemento costitutivo della norma consuetudinaria, cio che in altre parole significa:/’opinio e un presupposto necessario dell’obbligatorietd; daU’altro, si definisce Vopinio come convinzione di sottoporsi ad una norma giuridica, cio che in altre parole significa: l ’opinio presuppone un obbligopreesistente. La norma consuetudinaria non si costituisce se non c’e/’opinio; ma/’opinio a sua volta implica una norma gia costituita. Da questo circolo vizioso non si pud uscire che per due vie: o si considera/’opinio fondata sopra un errore, nel senso che la convinzione di sottoporsi ad una norma giuridica sia una convinzione erronea, per che riferita ad una norma ritenuta esistente ma in reafta inesistente./oppuresi ammette che vi sia una norma realmente costituitaprima delmanifestaris della convinzione, e allora si svuota di ogni autonoma validita giuridica la norma consuetudinaria. ’
42. See, e.g., Kelsen, Human Rights in the World n. 7, at p. 263; Mendelson, Human Rights in the World n. 3, at p. 279, particularly on the question of new rules departing from old ones: 'The concept of opinio juris, as traditionally formulated in terms of the recognition of a right or obligation, is definitively unhelpful when it comes to the creation of new rules. For if the practice is a new one involving a departure from (and breach of) previous law, as with the Truman Proclamation regarding the continental shelf, how can the State concerned possibly entertain the opinion that it is acting in accordance with the law?’
43. See, e.g., Sorensen, Human Rights in the World n. 8, at p. 50, according to whom this objection is 'too logical to be legally convincing’. See also Verdross, Human Rights in the World n. 6, atp. 640; B. Simma, Das Reziprozitatselement in der Entstehung des Volkergewohnheitsrechts (Munich, Fink 1970) pp. 33–34.
44. See Human Rights in the World n. 4.
45. See Human Rights in the World n. 57.
46. See, e.g., M. Bos, A Methodology of International Law (Amsterdam, North-Flolland 1984) p. 223; B. Cheng, 'Custom: The Future of General State Prattice in a Divided World’, In R.S. MacDonald and D. Johnston, eds., The Structure and Process of International Law (The Hague, Martinus Nijhoff 1983) p. 515.Contra: Mendelson, Human Rights in the World n. 3, atp. 281.
47. See, e.g., L. Le Fur, 'Regies generates du droit de la paix’, 54 RCADI(9?>5-lY) p. 198.
48. See, e.g., Thirlway 1972, Human Rights in the World n. 51, at pp. 53-54: 'needs of the international community’; Kopelmanas, Human Rights in the World n. 51, at p. 148. 65. See however Mendelson, Human Rights in the World n. 3, at p. 281.
49. Onthiscase, see, e.g., A. Bleckmann, 'Volkergewohnheitsrechttrotzwidersprachlicher Praxis?’, 36 ZaoRV (1976) pp. 374 et seq.
50. In the case of peremptory norms, the threshold for the change is higher, since there must be a double opinio iuris: first that a new practice is established as law and second that the relevant norm is also peremptory in nature. This requirement of 'parallelism in form’ renders more difficult the modification of peremptory norms of international law, which protect in most cases fundamental societal values. On the question see C. Rozakis, The Concept of Ius Cogens in the Law of Treaties (Amsterdam, North-Holland 1976) pp. 773 et seq.; G. J.H. van Hoof, Rethinking the Sources oflntemational Law ( Antwerpen, Kluwer Law Taxation 1983) p. 157; Kolb, Human Rights in the World n. 19, at pp. 85, 95.
51. Thus, for example, when some belligerents in the Second World War started to bomb indiscriminately (bombardement en tapis), this did not modify the rule relating to military targets, since not all the belligerents claimed it was legal (but referred to reprisals), whereas the neutral powers continued to assert the illegality of such bombings. See A. Randelzhofer, 'Flachenbombardementund Volkerrecht’, in H. Kipp, et al., eds., Um Recht und Freiheit, Essays in Honour ofF.A. von der Heydte, Vol. 1 (Berlin, Duncker & Humblot 1977) pp. 471 et seq.
52. See, e.g., A. Verdross and B. Simma, Universelles Volkerrecht, 3rd edn. (Berlin, Duncker & Humblot 1984) p. 362.
53. In this sense, e.g., Tomuscbat, Human Rights in the World n. 17, atp. 213. Sometimes, in similar cases, anew median rule emerges at more or less equal distance between the opposing claims. Thus, in matters of compensation for expropriation, the third world states claimed the right to expropriate without compensation (by virtue of the principle of compensation for previous exploitation), whereas the Western states claimed that expropriation could only take place against full and prompt compensation. Eventually, a quite hollow rule speaking of 'adequate’ or 'just’ compensation emerged. See Resolution 1803 (XVII), UNGA, 14 December 1962 and Resolution 3281 (XXIX), UNGA, 12 December 1974. On the question, see, e.g., E. Jimenez de Arechaga, 'International Law in the Past Third of a Century’, 159 RCADI (1978–1) pp. 297 et seq.; O. Schachter, 'International Law in Theory and Practice’, 178 RCADIpp. 321 (1982-V) et seq. 71. As to the European regional law, see, e.g., the Avis de droit of the Direction de droits international public of the Swiss Foreign Ministry, in 4 RSDIE (1994) pp. 601–603.
54. If there was previously such a common norm, Akehurst, Human Rights in the World n. 14, at p. 31 suggests a return to a common norm in inter-system relations: 'If the States in the first [regional] group have always dissented from the custom practised by the States in the second [regional] group, and if the States in the second group have always dissented from the custom practised by the States in the first group, then neither group is bound by the custom of the other group. The only solution, unless one is prepared to admit that there are gaps in the law (something which international courts and tribunals have never been willing to do), is to go back in history to a time when the rule accepted by both groups of States did exist, and continue to apply that rule.’ This position needs some qualification. The interpreter will need to assess whether the conditions for applying such an ancient rule still apply. It is submitted that this will often not be the case, and for that reason there will have been a change in the law leading to the two new regional systems. It is the dissatisfaction with the old rule which will have led to the new regulation; it would be odd to bind states of both groups - which will both have abandoned the old rule - to a rule which is contrary to their opinio iuris. In such cases, it is better to postulate a gap, which does not necessarily mean that there is no legal solution. At the level of direct inter-state contacts, negotiation will be necessary. If a judge is seized of a case, the parties have implicitly agreed that he will make every effort to fill the gap 'acting as a punctual legislator’, according to the general principle that the judge must, as far as possible, try to avoid a non liquet. Now, if one regional custom corresponds to the old rule, applied to a specific geographic area, and the other regional custom corresponds to a new rule, one might argue that the solution advocated by Akehurst should apply: the old custom, which was settled at the time of partial departure by some states, must be presumed valid and can thus be derogated from only inter se but not erga tertios.
55. See, e.g., Anzilotti, Human Rights in the World n. 6, at p. 68. For further references, see above, n. 6. 74. See, e.g., A.S. Hershey, The Essentials of International Public Law and Organization (New York, MacMillan 1927) pp. 24 et seq. As to this idea of common consent, cf., Oppenheim, Human Rights in the World n. 3, atp. 14: 'The basis of international law [rests] in the existence of an international community the common consent of whose members is that there shall be a body of rules of law. This common consent cannot mean, of course, that all States must at all times expressly consent to every part of the body of rules constituting international law.’ The Scotia (1871): 'Like all the law of nations, it [the law of the sea] rests upon the common consent of civilized communities’ (F. Desk, American International Law Cases, 1783 – 1968, Vol. 1 (New York, Oceana Publications 1971) pp. 05 et seq., p. 78).
56. Cf., K. Stmpp, 'Les regies generales du droit de la paix’ 47 RCADI (1934–1) pp. 303 et seq., distinguishing, for example, between a pactum taciturn simplex and a pactum taciturn qualificatum.
57. Cf., H. Kelsen (ed. by R. Tucker), Principles of International Law, 2nd edn. (New York, Holt, Rinehart and Winston 1966) p. 453.
58. See, e.g., M. Bourquin, 'Regies generales du droit de la paix’, 35 RCADI 1931-1) pp. 62 et seq. 78. One then navigated between real, presumed, assumed, emerging, tacit, etc. agreements.
59. As Bourquin, Human Rights in the World n. 77, at p. Ill very aptly said about the artifices of positivism: 'Or, on a beau retourner leprobleme en tous senn, la seule necessite logique qu ’on puisse decouvrir en l ’espece est celle de sauver lepostulat d’un systeme [i.e. pas d’obligation sans consentement]. Mais un systeme precisement qui conduit a cela ne se condamne-t-ilpas lui-meme?’
60. Cf., Kolb, Human Rights in the World n. 6, at p. 307.
61. Even if such a course may have some advantages (e.g., in preserving the judge from the criticism of having acted too boldly), if he can invoke a presumptive pact he can, in effect, say to the parties subject to his jurisdiction: look, you in fact agreed tacitly to this. 82. On this concept, see, e.g., Akehurst, Human Rights in the World n. 14, atpp. 23 etseq. See further T.L. Stein, 'The Approach of the Different Drummer’, 2 6 Harv. ILJ(1985)pp. 457 et seq.; J.I. Charney, 'The Persistent Objector Rule’, 56 BYIL (1985) pp. 1 et seq.; P.M. Dupuy, 'A propos de l’opposabilite de la coutume generate: enquete breve sur “l’objecteur persistant”’, in Melanges M. Virally (Paris, Pedone 1991) pp. 257 et seq.; D.A. Colson, 'How Persistent Must the Persistent Objector Be?’, 61 Washington L Rev. (1986) pp. 957 et seq.; J.B. McClane, 'How Late in the Emergence of a Norm of Customary Law May a Persistent Objector Object?’, 13 International Law Students Association Journal of International and Comparative Law (1989) pp. 1 et seq.; Conforti 1988, Human Rights in the World n. 31, at pp. 74 et seq.; G. Abi-Saab, 'Cours general de droit international public’, 207 RCADI(1987- VII) pp. 180-181; Weil, Human Rights in the World n. 13, at pp. 189 et seq.; I. Brownlie, 'International Law and the Fiftieth Anniversary of the United Nations - General Course on Public International Law’, 255 RCADI (1995) p. 42; M. Ragazzi, The Concept of International Obligations Erga Omnes (Oxford, Clarendon Press 1997) pp. 59 et seq.
62. See, e.g., the explanations in Carrillo Salcedo, Human Rights in the World n. 17, at pp. 92 et seq.
63. On this concept, see, e.g., Malanczuk, Human Rights in the World n. 4, at pp. 45–46. See also Mendelson, Human Rights in the World n. 3, at pp. 370 et seq. 85. It is sometimes denied that the General Assembly of the United Nations or other comparable international fora can give rise to binding international agreements (see, e.g., Mendelson, Human Rights in the World n. 3, at pp. 368–3 70). One of the principal reasons given is that the delegates to the GA have no formal treaty-making power. This argument cannot be accepted. We are not concerned here with the process of formal treaty-making, but with the possibility of expressing informally the will of their state. In important questions, such as those which can give rise to 'instant custom’, these delegates ordinarily consult their government, and there is no reason why this would not suffice. International law is not formalistic on such points. Moreover, there are clear examples of resolutions adopted at the GA which were considered to embody an informal agreement or even treaty. See, e.g., Resolution 24 (1) of 1946 whereby the United Nations decided the transfer of certain functions of the League of Nations to the United Nations.
64. See, e.g., Zemanek, Human Rights in the World n. 23, at pp. 220 et seq.
65. R. Baxter, 'Treaties and Custom’, 129 RCADI (1970–1) p. 64: 'It is only fair to observe that the proof of a consistent pattern of conduct by non-parties becomes more difficult as the number of parties to the instrument increases. The number of the participants in the process of creating customary law may become so small that the evidence of their practice will be minimal or altogether lacking. Hence the paradox that as the number of theah parties to a treaty increases, it becomes more difficult to demonstrate what is the state of customary international law dehors the treaty.’ See also Zemanek, Human Rights in the World n. 23, at pp. 221-223; Cheng, Human Rights in the World n. 62, at p. 532. 88. Baxter, Human Rights in the World n. 87, atp. 81. See also Thirlway 1990, Human Rights in the World n. 51, atp. 86.
66. Cf., Zemanek, Human Rights in the World n. 23, at pp. 220–221.
67. See S. Rosenne, League of Nations Conference for the Codification of International Law (New York, Oceana Publications 1975) Vols. II (pp. 22 et seq.)-IV. See also A. Raestad, 'Le problem e des eaux territoriales a la Conference pour la codification du droit international’, 7 Revue de droit international (1931–1) pp. 140 et seq.; J.S. Reeves, 'The Codification of the Law of Territorial Waters’, 24 AJIL (1930) pp. 486 et seq.; A.S. Bustamante y Sirven, La mer territoriale (Paris, Paul Goule 1930) pp. 189 et seq.; J.G. Guerrero, La codification du droit international (Paris, Pedone 1930) pp. 80 etseq. 91. Thus, for instance, a very exceptional provision, even if capable of analogous extension, will be interpreted strictly and a contrario: what is not mentioned in the provision will not be added to it. Conversely, an equitable general principle may be used for considerable normative extension by way of analogy. In the abstract, one may insist on the equivalence of both arguments, in practice only one will impose itself. See also U. Klug, Juristische Logik, 3rd edn. (Berlin, Springer 1966) pp. 97 et seq.
68. North Sea Continental Shelf cases, ICJ Rep. (1969) pp. 41–42, para. 72. On this dictum, see, e.g., Mendelson, Human Rights in the World n. 3, atpp. 318–321.
69. Mendelson, Human Rights in the World n. 3, atp. 318. 94. See Baxter, Human Rights in the World n. 87, at p. 62; K. Marek, 'Leprobleme des sources du droit international dans l’arretsur le plateau continental de la mer du Nord’, 6 RBDI (1910) p. 58; Akehurst, Human Rights in the World n. 14, at p. 50.
70. In this sense, see also Mendelson, Human Rights in the World n. 3, at ppiu. 320-321: '[T]he right test would be to see what the attitude of States actually was, not to proceed on the basis of unproven assumptions and a priori reasoning about “fundamental law-creating character”.’
71. ICJRep. (1969) pp. 40–41, paras. 66–69.
72. See Baxter, Human Rights in the World n. 87, at pp. 63-64; Akehurst, Human Rights in the World n. 14, at p. 48.
73. As to these terms, see Human Rights in the World section 2.4. 99. On all these criticisms, see, e.g., Akehurst, Human Rights in the World n. 11, atp. 48, along with the further references given in his footnote 5.
74. See Art. 42 of the Convention.
75. See Art. 19, letter c, Vienna Treaties Convention. 102. On this question, see United Nations, ed., Multilateral Treaties Deposited with the Secretary-General, status as at 31 December 2000, Vol. 1, ST/LEG/SER.E/19, pp. 96 et seq.
76. See St. Augustine, Sermons, no. 131, sect. 10.