1 Amongst the extensive literature preceding the 2001 ILC Draft Articles on State Responsibility for Internationally Wrongful Acts, see B. P. Sinha, Unilateral Denunciation of Treaty Because of Prior Violations of Obligations by the Other Party (1966); Simma, B., ‘Reflections on Article 60 of the Vienna Convention on the Law of Treaties and Its Background in General International Law’, (1970) 20 Österreiche Zeitschrift für öffentliches Recht 5Google Scholar, at 20–21, 83; M. L. Picchio Forlati, La sanzione nel diritto internazionale (1974), 71; Chinkin, C., ‘Nonperformance of International Agreements’, (1982) 17 Texas ILJ 387Google Scholar; R. Pisillo Mazzeschi, Risoluzione e sospensione dei trattati per inadempimento (1984), 343; S. Rosenne, Breach of Treaty (1985), 124; L. A. Sicilianos, Les réactions décentralisées à l'illicite: Des contre-mesures à la légitime défence (1990), 9 ff.; and L. A. Sicilianos, ‘The Relationship between Reprisals and Denunciation or Suspension of a Treaty’, 1993 EJIL 341; D. W. Bowett, ‘Treaties and State Responsibility’, Le droit international au service de la paix, de la justice et du développement, Mélanges Michel Virally (1991), 137; D. Alland, Justice privée et ordre juridique international (1994), 231; Grieg, D. W., ‘Reciprocity, Proportionality and the Law of Treaties’, (1994) 34 Virg. JIL 295Google Scholar; Weil, P., ‘Droit des traités et droit de la responsabilité’, in Montaldo, R. (ed.), El derecho internacional en un mundo en trasformacion: Liber amicorum en homenaje al profesor Eduardo Jiménez de Aréchaga (1994), 522Google Scholar; Dupuy, P.-M., ‘Droit des traités, codification et responsabilité internationale’, (1997) 43 AFDI 7CrossRefGoogle Scholar.

2 Cf. Gianelli, A., ‘Aspects of the Relationship between the Law of Treaties and State Responsibility’, in Studi di diritto internazionale in onore di Gaetano Arangio-Ruiz, Vol. 2 (2004), 757Google Scholar, at 805.

3 New Zealand v. France, Award of 30 April 1990, XX UNRIAA 215 ff.

4 Gabčíkovo-Nagymaros Project (Hungary v. Slovakia), Judgment of 25 September 1997, [1997] ICJ Rep. 7; cf. also the Air Services Agreement award of 9 December 1978, XVIII UNRIAA 416, para. 81.

5 Thus, Greece, in its Countermemorial of 19 January 2010, 11, para. 2.1 (cf. also 15–16); see ibid., at 11 ff., for the historical background of the dispute. The Countermemorial, as well as the other written defences and the transcripts of the pleadings, is available at www.icj-cij.org.

6 Ibid., at 14, para. 2.14.

7 1891 UNTS 1–32193.

8 See Art. 11 of the Interim Agreement; the use of the provisional denomination within the United Nations was recommended by the Security Council in Res. 817 (1993) of 7 April 1993, para. 2. This denomination is used by the ICJ and will henceforth be referred to also in the present paper.

9 See the Application, filed on 17 November 2008, at 6, para. 5.

10 Those defences, which were all rejected, addressed the interpretation of Art. 11 of the Interim Accord (paras. 84 ff. of the judgment); they further challenged the jurisdiction of the Court ratione materiae (since the dispute would not fall within the scope of the compromissory clause set forth by Art. 21(2) of the Interim Accord, ibid., para. 38) and ratione personae (the disputed acts allegedly should be attributed to NATO, not to Greece; furthermore, NATO and its member states should be regarded as indispensable parties to the proceedings, ibid., para. 44); the admissibility of the claim (para. 54); and the propriety of a decision on the merits (para. 60). Cf. on these aspects, Metou, M., ‘Application de l'accord intérimaire du 13 septembre 1995 (ex-République Yougoslave de Macédoine c. Grèce), Chronique de jurisprudence internationale’ (edited by Weckel, P.), (2012) 116 RGDIP 165Google Scholar.

11 Countermemorial, supra note 5, at 33 ff.

12 Ibid., at 37 ff.

13 Ibid., at 43 ff.

14 Ibid., at 52 ff.

15 Ibid., at 55 ff.

16 Ibid., at 60 ff.

17 Interim Accord, available at www.icj-cij.org, para. 153. The Court found only one instance of official use of the symbol in breach of the Accord to be proven.

18 This was actually the main defence raised in this regard by Greece: cf. the Countermemorial, supra note 5, at 163 ff.

19 In the Countermemorial, supra note 5, Greece expressly stated that it relied neither on its right to suspend the Interim Accord (at 163, para. 8.2) nor on countermeasures as circumstances precluding wrongfulness (at 164, para. 8.3), while, at the same time, maintaining that it would be entitled to do so (at 178, para. 8.29). This position was slightly modified in the Rejoinder, of 27 October 2010, where Greece relied on both the exception of non-performance and countermeasures as a justification for its behaviour (at 187, para. 8.3).

20 Para. 170 of the judgment; the Court refused to order ‘that the Respondent henceforth refrain from any action that violates its obligations under Article 11, paragraph 1, of the Interim Accord’, as requested by FYROM, since Greece's good faith in implementing the Court's judgment ‘must be presumed’ (ibid., paras. 167–168).

21 Dupuy, supra note 1, at 10.

22 XX UNRIAA 249–250, paras. 73 ff. Cf. Bowett, supra note 1, at 142; Grieg, supra note 1, at 379.

23 See Slovakia's Reply, 20 June 1995, at 85, para. 4.10 (available at www.icj-cij.org).

24 XX UNRIAA 251, para. 75.

25 [1997] ICJ Rep. 38, para. 47. Without mentioning it expressly, the Court hints here at the distinction between ‘secondary’ and ‘primary’ international legal rules; according to the approach suggested by Special Rapporteur Ago (1970 YILC, Vol. II, at 306) and accepted by the ILC in the context of its work on international responsibility, the former set forth ‘the general conditions under international law for the State to be considered responsible for wrongful actions or omissions, and the legal consequences which flow therefrom’, whereas the latter ‘define the content of the international obligations, the breach of which gives rise to responsibility’ (Report of the ILC on the Work of Its Fifty-Third Session, 2001 YILC Vol. II, Part 2, at 31; also Report of the ILC on the Work of Its Sixty-Third Session, UN Doc. A/66/10, at 69).

26 Art. 73 VCLT stipulates that its provisions ‘shall not prejudge any question that may arise in regard to a treaty . . . from the international responsibility of a State’ (cf. also Art. 74 of the 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations: since the two texts do not display significant differences for the purposes of this paper, reference will hereinafter be made only to the 1969 Convention).

27 Commentary to Article 29 of the 2001 Draft, Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 88.

28 Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 128 (emphasis added).

29 Cf. Commentary to Article 56 of the 2001 Draft, ibid., at 141.

30 Cf., e.g., Commentary to Article 69 of the ILC Draft on the Law of Treaties Concluded between States and International Organizations or between International Organizations, 1982 YILC, Vol. II, Second Part, at 67.

31 P. Reuter, Introduction au droit des traités (1985), 172 ff.; Dupuy, supra note 1, at 14; S. Forlati, Diritto dei trattati e responsabilità internazionale (2005), 3, at 168, 175 ff., argues that, from this perspective, the two sets of rules are part of a coherent system.

32 This conclusion was reached, as regards the EC Treaty, by the ECJ in Case 232/78, Commission/France, [1979] ECR 2730, at 2739. Some limitations to countermeasures as between international organizations and their members are set forth by Arts. 22(2)(3) and 52 of the ILC Draft on Responsibility of International Organizations (Report of the ILC on the Work of Its Sixty-Third Session, supra note 25, at 58, 65; since the solutions adopted in this text reflect, in many instances, those set forth by the 2001 Draft, hereafter reference will be made only to the latter as long as no significant differences arise). More frequently, treaty provisions specifically address situations related to necessity, at times precluding a contracting party from relying on the customary rule codified in Art. 25 of the Draft Articles on State Responsibility. The issue was addressed by the ICJ in the advisory opinion concerning the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Judgment of 9 July 2004, [2004] ICJ Rep. 136, para. 140. Cf. !!Binder, C., ‘Non-Performance of Treaty Obligations in Cases of Necessity’, (2008) 13 ARIEL 3Google Scholar; L. Salvadego, ‘Il ruolo della necessità nel diritto internazionale umanitario’, (2012) PhD thesis, University of Padova, on file with the author.

33 Cf. the Countermemorial, supra note 5, at 166.

34 See FYROM's Reply of 9 June 2010, at 158.

35 Memorial of 20 July 2009, at 94 ff.

36 Reply, supra note 34, at 147 ff.

37 Art. 60 VCLT reflects customary international law (cf. Legal Consequences for States of the Continued Presence of South Africa in Namibia (South West Africa) notwithstanding Security Council Resolution 276(1970), Judgment of 21 June 1971, [1971] ICJ Rep. 16, at 47; Gabčíkovo-Nagymaros, supra note 4, at 38), but the issue was not relevant to the case, since both FYROM and Greece are parties to the Vienna Convention. While the conclusion of the Interim Accord pre-dates FYROM's declaration of succession (made on 8 July 1999, cf. http://treaties.un.org), the latter has retroactive effect. Furthermore, the Interim Accord being a bilateral treaty, the complex rules set forth as regards material breaches of multilateral treaties did not come into play. For an appraisal of those rules, see, among many others, Simma, B. and Tams, C., ‘Article 60’, in Corten, O. and Klein, P. (eds.), Commentary to the Vienna Conventions on the Law of Treaties, Vol. 2 (2011), 1351Google Scholar.

38 Cf. Art. 60(3) VCLT. This notion enshrines a degree of discretion; the ICJ has, however, made it clear that a breach of a treaty, no matter how serious, does not allow for termination by the other party if it was caused by its own prior breach (Gabčíkovo-Nagymaros, supra note 4, at 67).

39 The VCLT does not set out the consequences of non-acceptance of the findings of the Conciliation Commission, and it is not altogether clear whether only acceptance by all the parties to the procedure could pave the way to actual denunciation or suspension (cf. Gaja, G., ‘Trattati internazionali’, in Digesto delle discipline pubblicistiche, Vol. 15 (1999), 344, at 367)Google Scholar. Subsequent practice does not shed any light on the issue, since the procedure set forth by Arts. 65–66 has never been relied upon so far.

40 Interim Accord, supra note 17, para. 163.

41 Ibid., para. 123. This functional connection with a previous unlawful act is also the element distinguishing retorsions from other unfriendly acts. Retorsions may, of course, be adopted in response to treaty breaches; however, they do not raise any doubts as to their lawfulness. Therefore, they are not specifically considered here.

42 Ibid., para. 163.

43 A formulation clearly inspired by Art. 60(3) VCLT is used in Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States), Judgment of 27 June 1986, [1986] ICJ Rep. 148, para. 10, of the operative clause, and in Rainbow Warrior, supra note 3, at 222.

44 Cf. Arts. 30–31 of the Draft. Cf. also the Commentary to Art. 49, Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 130.

45 Interim Accord, supra note 17, para. 164.

46 Ibid., para. 161.

47 Ibid.

48 Certain Norwegian Loans, Judgment of 6 July 1957, [1957] ICJ Rep. 25. Cf. Orakhelashvili, A., ‘The International Court and “Its Freedom to Select the Ground upon Which It Will Base Its Judgment”‘, (2007) 56 ICLQ 171CrossRefGoogle Scholar.

49 Cf. e.g., Aegean Sea Continental Shelf (Greece v. Turkey), Judgment of 19 December 1978, [1978] ICJ Rep. 3, at 17–18, paras. 39–40, as regards the continuing operation of the 1928 General Act for the Pacific Settlement of International Disputes.

50 Cf. his declaration appended to the judgment.

51 His separate opinion, para. 6, argues for ‘a decision a little less “transactional” in a matter in which the Court could have afforded to speak out’.

52 Interim Accord, supra note 17, para. 161.

53 Dictionnaire de droit international public (2001), 471. Cf. the Countermemorial, supra note 5, at 165, note 417.

54 See, e.g., C. Focarelli, Le contromisure nel diritto internazionale (1994), at 282; Grieg, supra note 1, at 400.

55 Supra note 51, paras. 10–11; cf. also para. 20.

56 Greece construed the exception of non-performance as a general principle of law (cf. the Rejoinder, supra note 19, at 189). The rule is drawn from national legal systems but this does not automatically imply its transposability in the international legal order under Art. 38(1)(c) of the ICJ Statute (cf. Gaja, G., ‘General Principles of Law’, in Wolfrum, R. (ed.), Max Planck Encyclopedia of Public International Law, Vol. 4 (2012), 370, at 373–4Google Scholar). Furthermore, as argued in the text, its independent scope in international law is very limited, whereas precisely the ‘general’ nature of principles is often stressed as one of the elements identifying this source of international law (cf. e.g., ibid., at 376; Kolb, R., ‘Principles as Sources of International Law’, (2006) 53 NILR 1, at 9)CrossRefGoogle Scholar. The exception might therefore be best seen as expressing a general principle (inadimplenti non est adimplendum) rather than a general principle in itself.

57 E. Zoller, Peacetime Unilateral Remedies: An Analysis of Countermeasures (1984), 15, at 27 ff.; Crawford, J. and Olleson, S., ‘The Exception of Non-Performance: Links between the Law of Treaties and the Law of State Responsibility’, (2001) 21 Australian Yearbook of International Law 65Google Scholar; Gianelli, supra note 2, at 797; C. Laly-Chevalier, La violation du traité (2005), 417–18. Cf. the Countermemorial, supra note 5, at 166.

58 Cf. Commentary to Part I, Chapter V, of the 2001 ILC Draft, Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 71, as regards circumstances precluding wrongfulness in general. Cf. also Commentary to Part III, Chapter II, ibid., at 128: ‘Countermeasures are to be clearly distinguished from the termination or suspension of treaty relations on account of the material breach of a treaty by another State, as provided for in article 60 of the 1969 Vienna Convention. Where a treaty is terminated or suspended in accordance with article 60, the substantive legal obligations of the States parties will be affected, but this is quite different from the question of responsibility that may already have arisen from the breach.’ Cf. already Special Rapporteur Fitzmaurice, Fourth Report on the Law of Treaties, 1959 YILC, Vol. II, at 41, para. 8; A. D. McNair, The Law of Treaties (1961), 573. However, the ILC's approach to the topic was not always consistent, as noted by Gianelli, A., ‘L'incerto destino dell'eccezione di non adempimento dell'accordo’, (2012) 95 Rivista di diritto internazionale 151, at 153Google Scholar.

59 Cf. the Rejoinder, supra note 19, at 188 ff.; Greece maintained that ‘insofar as the exceptio is to be applied as a separate principle, with a special regime and a scope different from that of countermeasures, it falls within the ambit of Article 56’ (ibid., at 190, para. 8.10). Crawford and Olleson, supra note 57, at 55, emphasize another point of contact between the exceptio and countermeasures, namely the fact that both may be triggered by any breach of treaty, not only by material breaches.

60 1992 YILC, Vol II, 2, at 23.

61 Cf. Draft Article 30 bis, in J. Crawford, Second Report on State Responsibility, 1999 YILC, Vol. II (Part One), paras. 316–329. Cf. also Chorzów Factory, PCIJ Rep. (26 July 1927), PCIJ Series A No. 9, at 31. In this perspective, the exception finds its basis not so much on reciprocity, but rather on other principles such as ex injuria jus non oritur: for an analysis of the two possible meanings of the exception, see Crawford and Olleson, supra note 57. An account ‘from the inside’ of the debate within the ILC may be found ibid., at 62, and, from a different point of view, in the separate opinion of Judge Simma (who was a member of the ILC at the time), paras. 26 ff.

62 Commentary to Part I, Chapter V, of the ILC Draft Articles on State Responsibility, Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 72.

63 Cf. again his separate opinion, para. 29. Judge Simma thus argues forcefully that ‘the . . . exceptio is to be declared dead’ (ibid., para. 26). For the reasons set out in the text, the present author respectfully disagrees.

64 Rejoinder, supra note 19, at 190.

65 Countermemorial, supra note 5, at 164, para. 8.6 (emphasis added).

66 Ibid.

67 Ibid., para. 8.3.

68 Diversion of the Waters from the River Meuse (Belgium v. Netherlands), Judgment of 28 June 1937, PCIJ Rep., Series A/B No. 70, Dissenting Opinion, at 77. Cf. also the dissenting opinion of Judge Anzilotti, ibid., at 50, and the ICSID arbitral award of 21 October 1983 in Klöckner Industrie v. Cameroon, 114 ILR 211. See also Nisot, J., ‘L'exception “non adimpleti contractus” en droit international’, (1970) 74 RGDIP 668Google Scholar, and the definition by J. Salmon quoted supra in the text, para. 4.

69 For the approach to the issue in France, Germany, and the United Kingdom, cf. Crawford and Olleson, supra note 57; for Italian law, see Realmonte, F., ‘Eccezione di inadempimento’, Enciclopedia del diritto, Vol. 14 (1965), 222Google Scholar, at 227; cf. further Karton, J., ‘Contract Law in International Commercial Arbitration: The Case of Suspension of Performance’, (2009) 58 ICLQ 863CrossRefGoogle Scholar.

70 Cf. Greece's Countermemorial, supra note 5, at 164, para. 8.3; see C. Campiglio, Il principio di reciprocità nel diritto dei trattati (1995), at 288.

71 Cf. Art. 49(1) of the 2001 ILC Draft Articles, Report of the ILC on the Work of Its Fifty-Third Session, supra note 25. See, however, Art. 52(3)(a) of the Draft, according to which countermeasures ‘may not be taken, and if already taken must be suspended without undue delay if . . . the internationally wrongful act has ceased’.

72 For the contention that no prior notification is required in order to invoke the exception, see the Rejoinder of Greece, supra note 19, at 163.

73 According to Special Rapporteur Crawford, ‘in its broader form the exception of non-performance should be regarded as based upon treaty or contract interpretation, performance of the same or related obligations being treated as conditional’ (‘Third Report on State Responsibility: Addendum’, UN Doc A/CN.4/507/Add.1, 363–366). Cf. Capotorti, F., L'extinction et la suspension des traités, (1971/III) 134 RCADI 417, at 548Google Scholar; Grieg, supra note 1, at 399; Crawford and Olleson, supra note 57, at 74. More generally on the role of reciprocity in the law of international treaties, see Virally, M., ‘Le principe de réciprocité dans le droit international contemporain’, 122 (1967) RdC 1Google Scholar; Simma, B., ‘Reciprocity’, in Wolfrum, R. (ed.), Max Planck Encyclopedia of Public International Law, Vol. 8 (2012), 651Google Scholar; E. Decaux, La réciprocité en droit international (1980), 257 ff.; Campiglio, supra note 70; A. Pietrobon, Il sinallagma negli accordi internazionali (1999).

74 As Greece put it, the Accord ‘constitutes a single transaction registering an exchange of considerations. No single article or provision, even if it imposes an obligation on one party only, can be treated as self-standing, in isolation from the rest. This is because such an obligation is part and parcel of a bundle of rights and obligations, accepted by one party in exchange for a corresponding bundle assumed by the other’. Countermemorial, supra note 5, at 31–2; ibid., at 28–9, for a more general discussion of the nature of the Accord. Cf. however the declaration of Judge Bennouna, supra note 50, at 1. On the difficulties of assessing conditionality, see Gianelli, supra note 58, at 156.

75 Cf. the ILC's Commentary to Art. 27(b) of the 2001 Draft Articles (Report of the ILC on the Work of Its Fifty-Third Session, supra note 25, at 86), a provision that fulfils a function similar to that of the exceptio in the context we are dealing with here.