The formal source of ius cogens in public international law

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The formal source of ius cogens in public international law

KOLB, Robert

KOLB, Robert. The formal source of ius cogens in public international law. Zeitschrift für öffentliches Recht , 1998, vol. 53, p. 69-105

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53(998),69-105 Zeitschrift für

üffentliches Recht

© Springel'-V erlag 1998 Printed in Austria

The FormaI Source of lus Cogens in Public International Law

Robert Kolb', Geneva

1. The Views ExpresseJ in Doctrine

IL The "Sophist's Refutations"; a critique of the arguments raised against various formaI sources potentially apt ta carry ius rogens norms

A. The Question of a Source SNi generis B. Custom

C. Multilateral Treaties D. General Principles of Law

III. Phi/osophia Positiva: sorne considerations favouring a flexible and global approach ta the formaI sources of ius (Ogens.

A. The travaux jwéparatoires of the International Law Commission and the Vienna Conference

B. Consensus as a Primary Source of International Law C. Cusrom, Treaties and General Principles

IV. A "Special" or "Regional" lm Cagens?

A. The Confusion in Doctrine B. The Field of Application of Art 53 C. Citcular Reasoning in the Deniers' Views D. In Praise of Regional lm Cagens

E. lus Cagens and Bilateral Treaties V. Concluding Remarks

Keywordr: lus cogens.

* The author wishes ta thank his friend and colleague, jean-Français Gareau, who adapted this article, (originally written in French) for the English language.

70 R. Kolb

J. The Views Expressed in Doctrine

In dealing wÎth a subject matter such as tbis one, ir Is good and proper, primo quaeritur, to follow the ArÎstotelian method of setting out the views of others before putting forward one's owo. Alas, a rhorough examination of these views, aImas! exclusively found in doctrinal writings, reveals mûst of them to be ill-considered, and more still ta be controversial. They are ill-considered, insofar as the fundamental considerations of substance (or material content) of peremptory narms seems ta have consigned the question of theit formaI source to a few rash, or Even worse, shallow obiter dicta. Moreover, controversy stems from an impresslve proliferation of articles dealing with ius cogens, yielding a wide array of opinions on the matter. Indeed, given the three primary sources listed in Art 38 para 1 of the Statute of the International Court of Justice (hereinafter, "the Statute") and aIl the mathematical combinations thereof, arguments in support of seven out of the eight possible solutions can be traced.

A. Sorne authors con tend that ius cogens requires a new, sui generis source.

Monacal reaches this conclusion by applying hierarchical thînking: the universal character and strict conditions of derogation that serve to distin- guish peremptory norms would presuppose the acquisition of this superi- or nature from their inception, and consequently through different means than other rules of international law. True for treaty and custom, this applies a fortiori to the general princip!es of paragraph 1 (c), seen as playing a subsidiary role in the genera! scheme of Arr 38.

For Onuf/Birney2, ius cogens is the result of an original consensus to that effect. Hence, it can only be articulated in multilateral conferences bring- ing together the international community as a whole, since one would be hard pressed to find the necessary meeting of minds elsewhere. This approximates the concept of an international legislative function: the emphasis placed on the role of opinio (manifested here as an "instant law") over diurnitas recalls that laid on recognition of the norm as having a peremptory character, stressed in Art 53 of the 1969 Vienna Convention on the Law of Treaties (hereinafter, "the Vienna Convention").

1 Monaco, Observations sur la hiérarchie des normes du droit international, Mélanges Mosler (1983) 106 et seqs. See generally Danilenko, Law-Making in the International Community (1993) 223 et seqs.

2 OmtflBirney, Peremptory Norms ofInternational Law: Their Source, Their Function and Future, 4 Denver Journal ofInternational Law and Poliey (1974) 193 et seqs. See also Caicedo PerdoJ1lo, La tcoria deI jus cogens en derecho internacional a la luz de la Convencion de Viena Sobre el derecho de los tratacios, 206 Revista de la Academia Colombiane de Jurisprudencia 261 et seqs. See generally Danilenko (fooenate 1) 245 et seqs.

The FormaI Source of llls Cogens in Public International Law 71

WhileJanir³ seems to ground ius (ogens directIy in naturallaw, Chris- temon^1, who also relies on the notions ofhierarchy and originating consen- sus, ca Ils upon an autonomous source without specifying how this new source might operate.

B. Others, like AJamoah5, Cahier6 , RonzittF, Thierry8, or Thirlway9, indi- recdy AgolO, Diaconu^ll, Fois¹², or Sztucki¹³, and implicitly Conforti¹⁴,

would acknowledge custom as the sole available source of peremptory norms. Still others, such as Brownlie¹⁵, Charles de VirJcher¹⁶, PauLI7 or

3 Janis, The Nature of Jus Cogens, Connecticut Journal of International Law 3 (1983) 302 .

• j Christensoll,Jus Cogens: Guarding Interests Fundamenral to International Society, 28 Virgînia Journal of International Law (1988) 592, 595. He speaks of "overriding community norms" as opposed to "uncoordinated, disparate mies of conduct derived from treaty and customary law", in effect leading to "two differenr normative systems". (On the whole, Christemon 1S very critical of the notion of im cogem).

:) See Carnegie Endowment Conference on Inrernational Law, Lagonùsi, Papers and Proceedings: The Concept ofIus Cogens in International Law (1967) 96.

6 Cahier, Cours général de droit international public, 195 RCADI (1985) 198.

7 Ronzitti, La disciplina dello jus cogens nella Convenzione di Vienna sul diritto dei trattati, 15 Comunicazioni e Studi (1978) 241 et seqs.

8 Thimy, Cours général de droit international public, 222 RCADI (990) 59: "Les normes dujlls cogens sont des normes de droit international général, c'est-à-dire des normes du droit coutumier.

9 Thirlway, International Customary Law and Codification (1972) 97: "The alleged norm does form part of 'general internationallaw', i.e. customary law". See also Martemen, lus cogens im Volkerrecht (1971) 102 et seq; P. M. Dujmy, Droit international public³ (995) 221; Bastid, Les traités dans la vie internationale (985) 102; Selso, Gli accordi internazionali confliggenti (1986) 336.

lO Yearbook of the International Law Commission (963) 75 para 23.

11 Diacontt, Contribution à une étude sur les normes impératives en droit international (1971) 100.

l ] Fois, La funzione degli accordi di codificazione nella formazione dello jus cogens,

Mélanges Ago (1987) esp 296 et seqs.

13 Sztllcki, Jm Cogens and the Vienna Convention on the Law ofTreaties - A Critical Appraisal (1974) 75.

14 Cmiforti, Cours général de droit international public, 212 RCADI (19S8) 129 et seqs.

l ) Brownlie, Principles of Public International Law⁴ (990) 513: "They are rules of

customary law .

16 Ch. de Visscher, Positivisme et Jus Cogens, 75 RGDIP (1971) 8 et seq. It seems uncertai n that multilateral treaties are here excluded: "Constituent par excellence le droit international général les normes coutumières ... " (8).

17 Pa/d, The Legal Consequences of Conflict between a Treaty and an Imperative Norm of General International Law Gus Cogens), 22 Osterreichische Zeitschrift rur offemliches Recht (971) 33: "Customary ruIes, to which j/lS cogem belong after ail .

72 R. Kolb

Reuter 18 ,speak of a customary base without allowing us to determine if, in

50 doing, they intend ta exclude aU other possibilities. At the Vienna Conference on the Law ofTreaties (hereinafter, "the Vienna Conference"), this stance found the support of Italy¹⁹ and, mast probably, of France²⁰ as weIl.

C. While a majority of authors ground ÎUJ cogens in either convention Of

custom, it is often difficult ta know wh ether the silence surrounding the

"general principles of law" implies their rejection outright, or whether it simply means that no conclusion has been reached on that point. Among those who expressly cast them out are Akehurst21, Puceiro RiPo!!22, Roza- ki.r²3, Shaw^24, Virally25 and, in a murkier fashion, Ziccardi^26; the general views of Aleksidze^{27 ,} Tunkin 28 or Verzijl29 on sources implicitly leave no

IH Reuter, Introduction au droit des traités, Armand Collin (1972) 139: "La Conven- tion de Vienne a donné cependant une indication favorable à la naissance coutumière, en ayant introduit la précision suivante: il s'agit d'une norme 'acceptée et reconnue par la communauté internationale des Etats dans son ensemble' Il s'agirait donc d'une coutume dans laquelle l'opinio juris présenterait un caractère particulier.

19 Unired Nations Conference on the Law of Treaties, Official Documents, First Session, New York, 1969, No F.70,V.7 page 311.

20 Ibid, Second Session, New York, 1970, No F.70.V.6 page 124 para 77.

21 Akehltrst, A Modern Introduction ta International Law⁴ (1982) 41; Akehurst, The Hierarchy of the Sources ofInternational Law, 47 BYIL (1974) 283.

22 Ptlceiro RiPoll, Desarrollos actuales del ius cogens: el fantasma rompe su hechizo, 3 Rev Uruguaya de derecho internacional (1974) 65 et seq,

23 Rozakis, The Concept of lus Cogens in the Law of Treaties (1976) 22, 58: "By definition, a general principle of law is not a norm, Ir is a general statemenr induced from or giving rise ta a number of rules of law; but it is not itself a norm in the sense that it has no legally binding character as such".

24 Shaw, International Law² (1986) 95: "It is also clear that only mIes based on custam or treaties may form the foundation of ius cogens norms".

25 Virally, Réflexions surle jus cogens, 12 AFDI (1966) 15, 25-28. See also Van HooJ, Rethinking the Sources oflnrernational Law (1983) 163 et seqs; DlIgard, Recognition and the United Nations (1987) 148.

2(, Ziccardi, Il contriburo della Convenzione di Vienna sul diritto dei trattati alla determinazione deI diritto applicabile della Corte internazionale di Giustizia, 14 Comuni- cazioni e Studi (1975) 1064 et seq.

27 Afeksidze, Legal Nature of lus Cogens in Contemporary International Law, 172 RCADI (1981) 259; also: Soviet Yearbook ofInternational Law (969) 149.

2H Tunkin, Theory of International Law (1974) 158; ILC Yearbook 1963, 69 para 26.

On his conception of sources: Ttmkin, Theory of International Law 91 et seqs, 199: "One must say very definitely that normative principles which would be corn mon ta the two opposed systems of law, socialist and bourgeois, do not exist".

29 Verzijl, International Law in Historical Perspective, vol 1 (1968) 85: "Such peremp- tory charaeter can attach to customary as well as ta treaty law", ta be read jointly with pp 60-63, where he assimilates general principles ta the convenrional or customary source.

The FormaI Source of lus Cogem in Public International Law 73

place for them; while Andrassy·3o, Cassese31 , Elias ^32, Geamanu ^33, Haraszti 34,

Jacqué³

5,

Nguyen Quoc Dinh/Daillier/Pellet⁴¹, Ruda 42 , Sinclair 43 or Ya.ueen⁴⁴ do not mention them at aU in this context. At the Vienna Conference, Trinidad

& Tobago⁴⁵, voiced an opinion specificaUy excluding general principles

from consideration.

D. Sorne erninent publicists would only accept custorn and general prin- ciples of law as possible sources. They are Dahm⁴⁶, .NIann⁴⁷, Mosler⁴⁸ and Barberis^{49 ,} the latter two ruling out rnultilateral treaties expre.uis verbis.

That was also the view taken by the Fedetal Republic of Germany50 at the Vienna Conference. Those who opt for this solution think that only

30 Quoted from Lagonissi (footnote 5) 46.

31 Cassese, Il diritto internazionale nel mondo contemporaneo (1984) 202.

32 Elias, The Modern Law ofTreaties (974) 180 et seqs.

33 Geamanu, Jus Cogens en droit international contemporain, Il Revue roumaine d'études internationales (1967) 62 et seq.

34 Hatwszti, Sorne Fundamental Problems of rhe Law ofTreaties (1973) 320.

35 Jacqué, Eléments pour une théorie de l'acte juridique en droit international public (1972) 157: "Le plus souvent, ces normes impératives trouveront leur origine dans les traités multilatéraux généraux la norme impérative peut également être d'origine exclusivement coutumière".

36 Jiménez de Aréchaga, Cours général de droit international public, 159 RCADI (1978) 66.

37 McNair, The Law ofTreaties (1961) 215: "They are mIes which have been accepted, either expressly by treaty or taddy by custom, as being necessary .

38 Menzel, Volkerrecht (1962) 106.

39 Meron, On a Hierarchy ofInternational Human Rights, 80 AJIL (1986) 17.

4() Morelli, A proposito di norme internazionale cogenti, 51 Rivista di diritto interna- zionale (1968) 1l0: "Non solo le norme consuetudinarie 0 comunque appartenenti ad una categoria sovraordinata rispetto a quella delle norme create da accordi, ma anche norme appartenenti a quest'ultima categoria possono essere di ,diritto internazionale generale' nel semo dell'articalo 50 [today Art 53] ed avere quindi il carattere di norme imperative".

41 Nguyen QHOC DinhlDai/lieriPellet, Droit international public⁵ (1994) 202.

42 Ruda in Lagonissi (foomote 5) 87.

43 Sinclair, The Vienna Convention on the Law ofTreaties (973) 130.

44 Yasseen in "L'élaboration du droit international public", Colloque de Toulouse, SFDI (1975) 207.

45 Conference (footnote 19) 355.

46 Dahm, Volkerrecht, vol 1 (1958) 17,

47 Mann, The Doctrine of Jus Cogens in International Law, Mélanges Scheuner (1973) 401: "This requires a custom ... or a general prindple of law".

48 Mosler, Jus Cogens im Volkerrecht, 25 Swiss Yearbook ofInternational Law (1968) 30,38.

49 Barberis, La liberté de traiter des Etats et le jus cogens, 30 ZaoRV (970) 44.

50 Conference (footnote 19) 319 para 33.

74 ^{R. Kolb}

custom and general principles can embody tules of general international law, as opposed to treaty law, specifically created by, and designed for the members of the conventional community.

E. Other jurists no less qualified, bearing in minci a small number of principles to be found at the top of the hierarchy, would grant status only to thase general principles of law. This approach, made fashionable during the inter-War by Hi/r/e^H and von der Heydte^S2, later became that of jaenicke⁵³, Miaja de la .iHue!a⁵

4,

F. Sorne "deniers" of Îus cogens would only and at the mast allow for its existence in rules binding solely inter partes, i.e. on a strict conventional basis. The rheoretical underpinnings here are not those of a general trai/é- loi, but that of part.icular law, strictly l.imited in its field of operation. The main proponent of this v.iew is Schwarzenberger^{57 .}

G. The following authors would regard aIl three primary sources, i.e.

treaty, custom and general principles of law, as capable of generating peremptory norms: Alston/Simma⁵⁸, Amerasinghe59 , Paul de Visscher⁶⁰, 51 Hade, Les principes généraux de droit et le droit des gens, 16 RDlLC (1935) 680:

il existe aujourd'hui déjà dans le droit des gens un certain nombre de principes généraux de droit [qui ont acquis] Hne valeur tellement absolue et jndiscutable que les Etats ne peuvent plus élaborer de normes qui leur soient opposées".

52 VOJl der Heydte, Glossen zn einer Theorie der allgemeinen Rechtsgrundsatze, Die Friedenswarre (1933) 297.

53 jde1licke, Zur Frage des internationalen ordre public, Berichre der Deutschen Gesellschaft für Volkertecht (967) 91. This author admirs also a ^il/J togem on the level of more concrete norms (SachJlorme1l); this particular ills cogens may emanate from custom, treaty or general principles (90).

5~ Miaja de la /vfite/a, lus cogens y jus dispositivum, Mélanges Legaz y Lacambra 11 (1960) 1141.

55 Qlladri, Dirîtto internazionale pubblico⁵ (968) 109.

56 Reimann, lus cogens im Volkerrecht (1971) 57: "Es gibr zwingendes Recht nur im Rahmen der allgemeinen Rechtsgrundsiitze".

57 Schwarzenberger, International Law as Applied by International Courts and Tribu- nais, vol 13 (957) 427; also Lagonissi (footnore 5) 88, 100, 103, where he admits the possibility of a customary Ù{J cogem, but daims ^ta have found no trace of it in an unstructured international society (103). The same argument is used against general principles (l00). See also Schwarzenberger, International lus Cogens? 43 Texas Law Review (1964) 455 et seqs. Even jf admitting customary-based iUJ cogens, Schweitzer, lus cogens im Volkerrecht, 15 ArchVR (1971) 222 et seq privileges their formation by treaty.

58 Alston/Silllllla, The Sources of Human Rights Law: Custom, Jus Cogens, General Principles, 12 Australian Yearbook ofInternational Law (992) 82 et seqs, 103.

'>9 AmerClSinghe in LagoniJJi (foomote 5) 90 et seq.

60 P. de Vi.rJcher, Cours général de droit international public, 136 RCADl (1972) 107.

He does not explain the reasons for this choice.

The Formal Source of lm Cogens in Public International Law 75 Gomez Rob!edoGt, Guggenheiml l\1arek⁶²) Hannikainen⁶³ (if in a very restric- tive way for genetal ptinciples), Kadelbach", Nahlik", Saladin"", Seidl- Hohenveldern⁶⁷, Suy68, TenekidesG9 , Wo!fke70 , Verdross/Simma ⁷¹⁾ or Verdross himself (with due regard for the evolution in his views) and for the often Imprecise quotes used ta buttress his arguments)72. Allowing for a small reservation with which we shaH deal more extensively later on, the present author also belongs to this category.7³

H. The only possible combination left, that of treaty and general princi- pIes of law) seems to have found no support in doctrine. Our research has so far yielded no advocate for this particular option. This should come as

61 Gomez Rohledo, Le ius cogens international: sa génèse, sa nature, ses fonctions, 172 RCADI (981) 103.

fi2 Guggenheim/Marek in Stmpp/SchlochallCr, Worterbuch des Volkerrechts, vol IIF (1962) 532.

63 Hannikainen, Peremptory Norms (lus Cogens) in International Law: Historical Development, Criteria, Present Status (1988) 216 et seqs.

64 Kadelhach, Zwingendes Volkerrecht (1992) 182 et seqs, esp 189.

65 Nahlik in Lagonissi (footnote 5) 97.

66 Saladin, Viilkerrechtliches lus Cogens und schweizerisches Landesrecht, 124 bis Zeitschrift des Bernischen Juristenvereins (1988): Die schweizerische Rechtsordnung in ihren internationalen Bezügen 72: "Volkergewohnheitsrecht, oder allgemeine Rechts- grundsütze oder omnîlaterale Vertrage'·.

67 Seidl-Hohmveldern, Volkerrecht^fi (1987) 150.

68 SlIy in LagoniHi (footnote 5) 74 et seq.

69 Tenekides in LagoniHi (foomote 5) 112.

70 Wolfke, Jus Cogens in International Law, 6 Polish Yearbook of International Law (1974) 151 etseqs.

71 VerdroJSISùmlla, Universelles Vülkerrecht3 (1984) 331: "Volkerrechtliches lUS co- gens kann jedoch nicht nur im Vertragswege, sondern auch aIs Volkergewohnheitsrecht oder allgemeiner Rechtsgruodsatz entstehen" (also 414).

72 VerdrosJ, Forbidden Treaties in International Law, 31 AJIL (1937) 572 et seq, where he admits a customary base as well as that of general principles; also Verdross, Jus Dispositivum and Jus Cogens in International Law, 60 AJIL (1966) 61: "A norm having the chatacter of illS cogens can practically be created ooly by a oorm of geoeral customary law or by a general or multilateral convention". However, one must not be misled by this sentence, like many authors have beeo. VerdroJS never departed from his acceptance of the concept of imperative general principles (such as the nuility of treaties contra bonos mores) binding in all cases. In the above quoted sentence, he speaks only of the volunrary creation of other peremptaty norms, since in his view general principles are oeither created not volunrary. See also, ta the effect that ^illJ wgens norms may emanate from custam, treaties or general principles, Yasseen, L'e!aboration du droit international public, Colloque de Toulouse (975) 206 et seq; Mann, The Doctrine of Jus Cogens io International Law, Essays in Honour of Scheuner (1973) 401; Nicololldis, La nullité de jlL~ cogens et le développement contemporain du droit international public (1974) 150.

73 See infra III.B.

76 R. Kolb

no surprise, sinee the (WQ most controversial sources in our context are paired here, white the more generally accepted one is lefe out.

Faced with chis vast array of opinions, we are tempced to reiterate as a starting point the query of Saint Thomas Aquinas: IlQuaeritur utrum sit tantum Ima veritas ". ,)"74 In 50 doing, we sha11 thereafter cake the view chat any exclusion of an existing formai source should find a satisfacrory justification. Hence, we shaH ficsr examine in furn the various arguments brought againsr any and ail possibilicies.

II. The "Sophist's Refutations": a critique of the arguments raised against various formai sources potentially apt

to carry ius cogens norms A. The Question of a Source sui generis

l. From his finding chat creaey and custom are hierarchically equal in imernarional law,15 Monaco⁷⁶ concludes that im cogem, undersrood as norms of a higher value on the hierarchical scale, necessarily requires a specifie source, dedicated ta express formally this superiority of substance.

Since a norro's rank or value in the hierarchy is here conferred through its source, the hierarchical concept must be seen as directly normative. It direcrly cceates the source needed foc the norms in question.

Ir seems that this reasoning is rooted in erroneous premises. The postulare that hierarchy can only esrablish itself through the source and not through the norm proper, or in orhec words, that this hierarchy necessarily rests outside rather than within the nocms, seems wrong.

Indeed, it is possible ta see in im cogem, undersrood as a special caeegory of norms, an exception to the principle of hierarchical equality between tceaty and custam. Conventional or custamary ius cogens mIes would be superior ta ordinary ru les flowing from the same sources exclusively by their special charaner of peremptary norms rather than by their formaI source. In other words, hierarchy is not necessarily linked ta the question of the formaI source. Normative hierarchy can ofeen be found within the rules of one single SOutce, this being the very essence of the generally known area of conflict of norms. Thus, for instance, Art 103 of the Charter

74 Saint ThomaJ Aqllinas, De Veritate, q.l, aA, beginning: '"Quaecitur utrum sic tanrum una veriras quia omnia sunt vera".

n On this, see e.g. Akehll1'Jt, The Hierarchy of the Sources of International Law, 47 BYIL (1974/5) 273 et seqs; also B,.ownlie (footnote 15) 3 et seq.

76 M01/aco (footnote 1) 606 et seqs.

The Formai Source of JIIS Cogel1s in Public International Law 77

of the United Nations establishes its own superiority over other interna- tional agreements.

More generally, sorne form ofhierarchy Îs necessary between the nocms of internationallaw but not, as an a priori, between its sources. If such was not the case, cooflicts of norms would remain insoluble. Hierarchical value is then often co be found in the norm itself, rather than in the source of the norm. Since this is true of particular norms, taken individually, one cannet see why the same conclusion should nor apply ta a whole categoty of dedicared nocms such as iriS cogens. On this last point, one should keep in mind that a norm's peremptory character relates co its material "con- tent", oot CO the formai "container" or support that carry it.⁷⁷ The preceding reasoning is especially true in international law where the formai sources as such are largely devoid of a pre-established hierarchical order.

2. One must concede co Onuf/Birney78 that an original, widespread con- sensus. formulated in the context of an international conference, can, independendy of any orher formai process, give ri se ta ius cogens,79 Never- theless. ir is hard to see why any orher means by which consensus can be expressed in the international community. such as treaty or. more limita- tively, custom, should not be able to serve the same purpose.

3. The view that finds ius cogens roored directiy in naturallaw⁸⁰ as a direct source of law stems from a regrettable misconception of the concept. and leads on a slippy slope. The role of the jurist is ta apply notms, termed

"juridical" because of their consecration as positive law through the sources of a legal system.

It is of course possible ta con tend that the material origin of ius cogens (or at least of the highly moral rules 50 often given as an example of it) is natural law. This is another matter enrirely. Still, rhat is nothing partic- lIlar co iUJ cogens.

Natural law doctrine seems the only acceptable theoretical basis founding legal obligation in its very core. Yet the supra-positive (über- positiven) norms iure naturati are, in general, factors that should inspire the decisions of a given legislacor; they are Jess directly controlling in legal terms. They serve as the basis of the system, a system that by definition can ooly be grounded in an external element, both hereronornous and ontolog-

77 $ee infra 1II.A.a.

78 OI1I1f1Bil'l1ey (foomoee 2) 193 et seqs.

79 See infra II1.B.

fj() See supra texc and foornoce 3.

R. Kolb

ieal, able ta guarantee its minimal axiological unity. By virrue of their high level of abstraction, itself due ta their overarching supremacy, these super-norms are often condemned to the rale of a general delineating frame. As such, they can only tarely determine conetete solutions: ta be complete, they call1lpon the action, and thus the freeclom of Man. One 1S again reminded here of Saint Thomas Aqttinas and his ((analogia entis"81, proceeding from the idea that the divine essence can be found in aU the beings of Creation, albeit in varying levels of intensity. One can picture a large pyramid, where the abstracr essentia, Even as it gets progressively weaker as one moves downwards on the structure's degrees (i.e, towarcls higher levels of "concrete realisation"), provides the whole system with its unit y and axiology. Ali references ta Gad put aside, this is a fairly good representation of the juridical normative system. AH its norms must tend towards the bonum commune for it alone can provide a real basis of obligation and not only of constraint; metaphorically speaking, the mathematical sign of the norms must be positive. Evaluating the common good is a human endeavour: it is therefore incomplete, relative, and always in progress. The legal norm is essentially formaI, for its content must be determined and val.idated by an act granting it positive value. Yet it has a "material" dimension that emanates from its participation in the su- preme normative values and that densifies itself more it moves upward the described pyramid. This is so because law is at the same time a value and a positive fact.Thus, constitutional norms or general principles are more value-oriented than more specifie, technical rules. It is at this highest points that naturallaw can seek normative incarnation. It then touches to the aspects that transcend human subjectivity to attain certain, absolute value. Where else for instance can we put categories like the prohibition of genocide? When a positive rule attempts to derogate from that exclu- sive purview, that domaine réservé of objective justice, it is nullified by the norm of naturallaw. Interestingly enough, the modern doctrine of human rights seems to have adopted a similar conceptual frame, distinguishing a formaI normative periphery from a material hard core being absolutely inderogable when limitations of individual freedoms occur eWesensge- halt)82. The norm that contravenes the lowest axiological denominator common ta the whole legal arder may still be applied for a time: that does not deter from the fact that it has in our view effectively cast itself out of that order, that it has become non-faw. Ifhuman conscience can persist in

St Saint ThonJas Aqllillas, Summa theologica 1, 13, 5.

!l2 E.g. von Hippel, Grenzen und Wesensgehalt der Grundrechte (965); Haeber/e, Die Wesensgehaltgarantie des Art. 19 Abs. 2 G(,~ (1972); J. P. Müller, Elemente einer schweizerischen Grundrechtstheorie (1982) 141-155.

The FormaI Source of lils Cogens in Public International Law 79 ertor for a while, a legal order cannot do so without sacrificing its coherence.⁸³

One can see how this perception of naturallaw, linking freedom, will and necessity, manages, contrary to the blame often put upon such doctrinal constructs, ta respect aIl the polychromatic qualities of reality.

Hence, natural Law in its direct applicability is, in th.is author's view, a

"state of necessity" law rather than a "daily management" Law. Far from replacing the formaI sources, it provides the farthest and absolute limits to the flexibility of the substance they shape. This explains why the opinion of those who, in rather muddy fashion, seem ta base iriS cogens directIy on naturallaw, as a formaI source sui generis, cannot be sustained.

4. In neither the International Law Commission nor the Vienna Confer- ence was a similar line of reasoning induding resort to a separate source for ius cogens ever entertained. Most of the experts and delegates relied instead

113 On aU these points, see chiefly the essential contributions of Radbrllch, RedIts- philosophie^H (1973) 339 et seqs ("Der Konflikt zwischen der Gerechtigkeit und der Rechtssicherheit dürfre dahin zu losen sein, dass das positive, durch Satzung und Macht gesicherte Recht auch dann den Vorrang hat, wenn es inhaltlich ungerecht und unzweck- massig is.t, es sei denn, dass der Widerspruch des positiven Gesetzes zur Gerechtigkeit ein so unerrragliches Mass erreicht, dass das Gesetz aIs 'unrichtiges Recht' der Gerechtigkeit zu weichen hat", 345); andA. Kaufmann, Rechtsphilosophie im WandeF (1984) esp 7 et seqs, but generally aIl the opus. In internationallaw, Salvioli, Les règles générales de la paix, 46 RCADI (1933) 15, writes: "si un traité existe et règle une matière donnée, il faut l'appliquer, même s'il eût été préférable que la matière soit réglée par des règles plus proches de la justice, à moins que le contraste avec les normes fondamentales de la justice ne soit accusé au point qu'il convienne de faire prévaloir le principe de justice violé par le traité, sur le principe du respect des pactes". This idea goes back to greco-roman philos- ophy, having been defended by Aris/otle, the Stoïcs, Cicero and Senera. They fought the opinion of Carneades and the Epicurians, acconling to whom justice was merely a human thing, based upon a convention between men trying to follow the lessons of practical experience. The naturalists upheld the existence of a higher concept of justice, tbat they daimed identical to naturallaw as dîctated by rlgbt reason, the recta ratio. This law was seen as etetnal and immutable. If peoples and princes should enact positive laws contrary to the supreme notms that predate any political community, these laws, white not losing their formallegal quality, could not be construed as reallaw, orjlls ("Neque opinione sed nutura esse ius", Al'istotle, Nichomacbean Ethics, 1134 b, 1,2. See also Sophoc/es' Antigone;

Cicéro, De legibus, 1, 10; l, 14-16. De republica, 3,11; 3,12; 3,19; 3, 22;Seneca, Letters to Lucilius, 4, 12; 22, 1). Those idcas will be integrated in Christian philosophy: see e.g.

Saint AlIg!fJtine, De Iibero arbitrio, l, 15 P.L. 32, 1229; 1, 5, 11 P.L. 32, 1227; Ennarra- riones in psalmos, 145, 15, P.L. 37, 1894: "Nec ius dicendum est si iniustum est ... "; De civitate Dei, IV, c 4; and Saint Thomas l\..qttinaJ, Summa theologica, II, 1,95,2 (tex cormpta).

This idea, even when reduced in scope, has always lied at the heart of naturallaw doctrines.

This centuty has taught us how unavoidable it can be (evcn jf it appears awkward), if only through the rÎse of Hitlerism.

80 R. Kalb

on conventional Of customary means.⁸⁴ This should serve as a reminder rhat ius cogens is at heart a matter of substance, not of source.

B. Custom

Sed contra: Custom is the mûst commonly accepted SOUfce of ius cogens. The rare authors who reject it rely again on a hierarchic argument, hinging upon the supremacy of general principles of law. Reimann Of von der Heydte⁸⁵• for whom ooly general principles can produce fus cogens, start from the correct assumption that sorne general principles are absolute and superior ta custom Of treaty tules. Among those we fiod iipacta vel consuetudo sunt servanda^Jl, or, more generally, the essential conditions of validity of trearies and eus tom which must pre-exist them if one 1S to avoid falling into a circular argument. 86 The essential conditions on acquisition of internationallegal personality are also superior ta ordinary treaty and custamary rules if one is ta avoid once again circular reasoning. For this authors, similarly, neither treaty rules nor custom (because of the require- ment of opinio iuris) can derogate from the principle prohibiting obliga- tions contra bonos mores or good faith. Such are the hierarchically supreme principles through whîch one can gauge what type of derogations are allowed by treaty or custom. Therefore, peremptary norms can only emerge out of this superlative source, since the submission of a body of norms labelled "imperative" or "peremptory" to a superior one, able ta restrict it, would be unthinkable. One would be facing a contradiction in terms.

Respomio: Almost all of these and like claims predate the Vienna Conference, lessening their relevance to the further Evolution of the question. From the outset, this line of argument may appear unimpeach- able, for one who believes the premises ta hold true;87 nevertheless, one must come ta the conclusion that it partakes of the logical error of incorrectly transposing from one plane ta another.

84 See infra III.A.a and footnore 141.

85 See supra I.E.

86 See Qtladri, Cours général de droit international public, 113 RCADI (1964) 350.

87 Such is not the case for Mos/er (footnote 48) 30, or for Schelfner, Conflict of Treaty Provisions with a Peremptory Norm of General International Law and its Consequences, 27 ZaüRV (967) 525 et seq, who lîmit the the scope of general principles by distinguish- ing them complecely from the structural tules necessarily presupposed in a legal arder (Funktionsnormen), 5uch as pacta sunt servanJa, gooJ faith, equity, etc. For them, these norms are logically and hence, pre-juridically binding, touching upon the famed point of Archimedes. This is all in the end a matter of terminology.

The Formai Source of lm Cogens in Public International Law 81

The alleged incapacity of an "infetior" source ta carry ius cogens does not follow from the hierarchic argument, for the problem is not one of hierarchy nor of production of norms (hence a "sources problem"), but one of collision of norms. Hierarchy is a matter of precedence. It does not alter the intrinsic character or qualification of norms. The eventuality of a conflict of peremptory norms does not suffice to disqualify their norma- tive nature. It should lead one to search for a casuistic solution, accommo- dating the conflicting norms by differentiatîng their sphere of applica- tion. An affirmation to the contrary would be akin ta a statement that, in domestic law, peremptary rules cannot be enacted by laws, because the Constitution is hierarchically superior ta laws. But supreme rank and peremptory character are not synonymous.

In fact, universal norms expressing ius cogens in internationallaw very often convey moral contents, contents which would make a collision with general principles highly unlikely.88 Moreover, we have seen⁸⁹ how the system's normative hierarchy is a matter of substance rather than of sources. General principles, limited in number as weIl as in scope, can accommodate a wide array of norms either compatible with them or operating in fields that they do not regulate. They are that much less predestined to exclude peremptory norms at other levels that they them- selves tend to crystallise their essence in fields other than their own through conventional or customary means. To find against eus tom, espe- cially on the strength of the superior value of general principles, does not strengthen the international public order. This is quite paradoxical, since authors who defend this position are of a school of thought that would, on the contrary, put this policy goal at a premium.

88 Dahm (footnote 46) 17, and von der Heydte (footnote 52) 296 et seq, daim that a real conflict between custom and general principles Îs not possible. Custom requîres opinio iuris to accompany the materîal action. Such opinio ùtris cannot aim to depatt from a rule deemed necessary to a legal order: Law cannot contradict itself. Thus, a practice commry to such a principle would be eithet impossible (e.g. abolition of the mie parta Hint servanda through a convention, which would, by way of contradiction, represent a logical impossibilîty - not ta be confused with a simple violation of the principle), or nan-customary by lack of opinio iNtis (RerhtsiiberzeJtgung). Von der Heydte speaks in such a case of "gewohnheitsmassiges widerrechtliches Verhalten der Staaten" (297). This view brings a strong element of Sallen in the definition of custam, usually seen more in rerms of sociology. The presupposed element inherent to this doctrine is that opinio ù/ris is characterized by an objective element of conformity with certain primary Iegal mies (emphasizing the "iNtis"), not merely by the observation of convictions and effective pracrice (emphasizing the "opinio"). In this view, essence cornes before existence, by opposition to the traditional approach which places existence before essence, and qualifies it a posteriori.

119 See supra II.A.a.

82 R. Kolb

Having put ta rest this objection, we can consider, prima Jarie, that custom is an acceptable formaI source of ius cogens,

C. Multilateral Treaties

1. On the conventional sicle, one must distinguish tWQ situations. First the possibilîty of creating ius cogens norms by a universal multilateral treaty; this we will DOW examine. Second, the possibility of existence of a parricular or regional ius cogens slnce it will often be embodied in a convention between a limited number of states (regional custom not being neglected ); to this we shaH revert later.^9o

2. Sed contra: The main stumbling black of the recognition of convention- al fus cogens 1S the relativity of treaties ratione personae. By virtue of the principle res inter alios acta, treaties could only ever creare law resrricred ro a defined communiry, and never general inrernarionallaw.⁹¹ Then, rhe rerms "general inrernarionallaw", as rhey figure in Arr 53 of rhe Vienna Convention, would arguably refer exclusively to cusromary law.⁹² This approach also suggesrs an apprehension towards imparting a "legislative function" ro such multilateral instruments, especially if one sees them as able to generate binding treaty commîtments for third-party states.

Responsio: The most obvious objection to this assertion is that one can envisage a truly universal treaty, literally bringing together aIl states.⁹³ But no treaty, not Even the Charter of the United Nations, has ever attained this perfect level of acceptance.⁹⁴ Of course, the "constitutional"

princip!es embodied in the Charter have been accepted by all, but ,hat argument is not decisive, sinet such principles then belong to the province of customary law.

The main point is that this is again a petitio princiPii. One poses first that ius cogens must belong to general international law, then deduces

?O See infra IV.

91 For instance, Cheng, Custom: The Future of General Stace Practice in a Divided World, in MeDonaldljohnstolJ (eds), The Structure and Process of Internationallaw (1983) 526 et seq; Fitzllldllr;ce, Sorne Problems Regarding the FormaI Sources of International Law, Symbolae Verzijl (1958) 153. See on this point the critique of Mendelson, Are Treaties Merely a Source of Obligation? in Blttler (ed), Perestroika and Internationallaw (1990) 81. et seqs. As applied to ilts cogms, see e.g. Sciso, Gli accordi internazîonali confliggenti (986) 335 et st.'qs, 394 et seqs.

?2 A view justly criticized by CajJotorti, l'extinction et la suspension des traités, LH RCADI (1971) 522.

93 Bar/m'is (fnotnote 49) 45 accepts the treaty as a valid bearer of peremptory norms soldy in this theoretical case.

The FormaI Source of bIS Cogens in Public International Law 83

therefrom that treaties cannot serve as a source of such law, with the analysis of such "inherent" inability to produce general norms going no further than grammatical, or indeed talltological exegesis. This parti pris will become even more questionable if one considers the depth of the doctrinal debates dealing with potential exceptions to the principle of telativity.95 This shows that the principle of relativity is far from being absolute or even logically necessary. An a priori conception of the treaty as a means able to produce only "speciallaw" is ill-adapted to the interna- tional order, where law-givers and subjects are the same entities. From this stems the problem of producing general law in the international society. Total exclusion of the treaty would be tantamount to rendering absolutely impossible the creation of voluntary general internationallaw.

Such a course would be of doubtful value, given the primary importance of the conventional process, and of codification in particular, in the management of contemporary world affairs.⁹⁶ As long as the question is put in terms of relativity, a comprehensive answer remains out of reach.

What really counts is the effect the norm created has on states, rather than the effect of the source per se. Ir should not be forgotten that if universal custom is said to be binding upon aU states, its normative elaboration will not requite the participation of each and every one of them. It even knows a constraint which, if not akin to the rule pacta tertiis nec nocent nec prosunt, is not to be neglected nevertheless: the exception of the persistent objec- tor.⁹⁷ In that sense, it is not necessarily really universal either. One can even imagine a multilateral treaty ro whom fewer states are not parties than there are persistent objecrors to a customary rule.

In this case, the status of "third-party states" towards such heterono- mous norms, and thus the distinction between "general" and "special"

law, should be a matter of degree, not of category of sources. The crucial point 1s this: can respect for the "externally determined" rule of iUJ cogens be forced upon the non-participating state? Ir is hard to see why this would be possible in the case of eus tom (probably even against a persistent objector⁹⁸), but never, ex dogma pacta tertiis, for states not party ta an

94 See Gomez Rob/edo (foomore 61) 96.

9) E.g. Ngllyen QlfOC DinhlDaillieriPellet (footnote 41) 2.39 et seqs, esp 245 et seqs on

"objective regimes", etc.

96 See infra III.C.b.

97 See the Anglo-Norwegîan Fisheries case, IC] Reports 1951, 131.

911 This view is shared by a majorîty of authors: Henkin, General Course of Public International Law, 216 RCADI (1989) 60; BrowJllie (foornote 15) 11 footnore 56; IIaJl- nikainen (foomore 63) 231 et seq; BarberiJ, Formaci6n del derecho internacional (1994) 111;

Rozakis (foomore 2.3) 77; Thirlway (foornote 9) 110; Yasseen (footnote 44) 207; Ziccardi (foomore 26) 1065. Against rhis trend; \f1ol/ke (foomote 70) 149; Chtlrney, The Persistent

84 R. Kolb

otherwise very widespread multilateral agreement, states who oft-rimes are not Even opposed to the tules spelled out therein, as persistent ob j ectors are.

This approach is the ooly one that fits the notion of ius cogens as it was unclerstood in the International Law Commission and at the Vienna Conference, where the ability of trearies ta create peremptory norms was largely admitted.⁹⁹ Moreover, one must keep in minci that no requirement of unanimous acceptance (that is, on the part of each state individually) of a given norm was retained for the tule ta Emerge as jus cogens and acquire imperative and universal charaeter.^IOO

From thenee ODe can affirm that a norm produced within a particular but large community can, by clefinition, establish itself on the general plane. The nature of a treaty as giving rise to such particular law would then pose no obstacle a priori to its capacity to enunciate peremptory norms.

Contrary ta what Cahier ^{10 l} daims, sorne "legislative effects" are thus inevitable in an international community that has attained our cutrent level of integration. Those effects find themselves integrated in positive law. IUJ cogens is, by its very essence, a legislative concept.

Objector Rule and Customary International Law, 56 BYIL (985) 3 et seq footnote 9, 19 et seq fONnote BI. For further references, see Ragazzi, The Concept of International Obligations Erga Omnes (997) 59 et seqs.

99 ILe Yearbook 19661II, 248 para 4, and Conference (footnote 19) 293 et seqs.

100 See the explanation of Yasseen, President of the Drafting Committee, in Confer- ence (foomate 19) 472 para 12: "There was no question of requiring a rule ta be accepred and recognized by aU States. Ir would be enough if a very large majority did sa; that would mean that, if one State in isolation refused ta accept the peremptory character of a rule, or if that State was supparted by a very sm ail number of States, the acceptante and recognition of the peremptory character of the rule ... would not be affected". See also infra text and foomote 148, where the excellent formula of Capotorti is reproduced. In Akehltrst (footnote 75) 284 et seq, the examples given of States having allegedly opted for unani- mous global acceptante of a rule before it can become peremptory (see his footnore 5) are not necessarily convincing, for those States speak simply of "universai" acceptation or recognition: if is not at ail certain that, for them, "universal" is taken to mean "absolutely unanimous" rather than "gathering a vast majority", An interpretation favouring unanim- iey is, as always, untealistic (what matters is to weigh, not to count), if only because if a dispute arises, it is highly probable that at least one State will contest the normative value of the rule.

1()1 Cahier, Cours général Je droit international public, 195 RCADI (1985) 198 et

seq, 203: "On ne saurait le répéter assez, la conception que j'on se fait encore aujourd'hui du principe de l'égalité des Etats, de la notion de souveraineté, et de la structure même de la société internationale empêchent une majorité d'Etats de légiférer à l'encontre J'une minorité" (198).

The Formai Source of lus C(lgens in Public: International Law 85

3. Sed contra: RonzittP02, among others,103 argues that treaties codifying norms of peremptory character, or norms essential to the functioning of international society, are an expression of law that is either already customary or soon to be part of custom. Those customary rules would then be the ones binding all states, and not the treaty rules per se. Examples often given include the Charter of the United Nations and the Vienna Convention on the Law of Treaties.

Respon.fio: This view is mistaken, in that it confuses matters of fact and matters of principle. To say that codification treaties often express in fact customary rules is correct; ta say that they necessarily have ta do sa is begging the question. The customary nature of a given rule is a question of state practice, a matter of cases in point. Forcing custom ta caver a priori all cases where a treaty would carry peremptary norms would artificially stretch the concept ta a purely fictional degree. In truth, there is today a tendency towards "making everything custom" .104 Its illusory conse- quences show, for example, in these dual assertions from Conforti:^lOS on the one hand, he thinks custom is the only possible source of iu.f cogens; on the other, he identifies the very heart of ius cogens in Art 103 of the Charter.

It is very hard indeed ta believe a rule establishing the primacy of Charter obligations over any competing treaty commitments to be customary, i.e.

binding also non-members of the United Nations!

4. Sed contra: The same Ronzitti 106 contends that his assessment of custom as the sole source of ùu cogens finds a confirmation in the views expressed by states at the Vienna Conference.

Re.fponsio: Ronzitti has tracked down and refers ta every one of the quite rare statements that support his theory.l07 The vast majority of partici-

102 RrJnzitti (foomote 7) 293, refers ta the Vienna Convention itself that "pressupone l'esistenza dello jm cagens".

103 Fois (foomote 12) 296 et seqs, tends towarcls this view, leading him to condude that "ac:c:ordi di codificazione non sono immecliatamente fonte di norme cogenti, pur conc:orrenclo alla loro formazione" (305).

[()1 Weil caUs this phenomenon the "cltstomary nebula" ("nébuleuse coutumière"), in:

Le droit international en quête de son identité (Cours général de droit international public), 237 RCADI (1992) 160 et seqs.

Hl5 Con!orti (foomote 14) 129 et seqs.

JOli Ronzitti (foomore 7) 203.

107 Notably ltaly (footnote 19) and France (footnote 20). He also bases his findings on the United States' declaration stating that "ta give a nmm of custamary inrernationallaw a peremptory character, State practice must be unambiguous" (see Conference [foot- note 20] 102 para 22, emphasis added): he believes this sentence reveals an implicit recognitiun that the peremptory norm must be customary, since anly custom is men- tianed. But this reading îs not necessarily the right one, and it is plausible that the reference ta custom was made without prejudice ta other eventual sources. Moreover State