¹ Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras), Application by Nicaragua for permission to intervene, Judgment of 13 September 1990, [1990] ICJ Rep. 92.

² 1945 Statute of the International Court of Justice (ICJ Statute) Art. 62.

³ Cf. G. Morelli, La sentenza internazionale (1931), 217; G. Morelli, ‘Fonction et objet de l’intervention dans le procès international’, in J. Makarczyk (ed.), Essays in International Law in Honour of Judge Manfred Lachs (1984), 403; W. Friede, ‘Die Intervention im Verfahren vor dem Ständigen Internationalen Gerichtshof’, (1933) ZaöRV 1, at 49; M. Scerni, ‘La procédure de la Cour permanente de justice internationale’, (1938) 65 RCADI 561, at 652; E. Hambro, ‘The Jurisdiction of the International Court of Justice, (1950) 76 RCADI 121, at 149; V. S. Mani, International Adjudication: Procedural Aspects (1980), 248 ff.; A. Davì, L’intervento davanti alla Corte internazionale di giustizia (1984); W. Fritzemeyer, Die Intervention vor dem Internationalen Gerichtshof (1984), 109 ff.; G. Cellamare, Le forme di intervento nel processo dinanzi alla Corte internazionale di giustizia (1991), 56 ff.

⁴ Cf. Continental Shelf (Tunisia v. Lybia), Application by Malta for permission to intervene, Judgment of 14 April 1981, [1981] ICJ Rep. 3; Continental Shelf (Lybia v. Malta), Application by Italy for permission to intervene, Judgment of 21 March 1984, [1984] ICJ Rep. 3.

⁵ Cf. Continental Shelf (Tunisia v. Lybia), ibid., at 23 (Judge Oda, Separate Opinion); Continental Shelf (Lybia v. Malta), ibid., at 35, 84, 115, 148 (Judge Mbaye’s Separate Opinion and Sir Robert Jennings’, Judge Ago’s, and Judge Oda’s Dissenting Opinions, respectively).

⁶ Cf. Land, Island and Maritime Frontier Dispute case, supra note 1, at 135 ff., para. 102 ff. On this judgment see K. Oellers-Frahm, ‘Überlegungen anläβlich der Zulassung der Intervention Nicaraguas im Streit zwischen El Salvador und Honduras’, (1990) ZaöRV 795; M. Kohen, ‘La requête à fin d’intervention du Nicaragua dans l’affaire du différend frontalier, terrestre, insulaire et maritime (Salvador/Honduras). L’ordonnance de la Cour du 28 février 1990 et l’arrêt de Chambre du 13 septembre 1990, (1990) AFDI 341; M. Evans, ‘Case concerning the Land, Island and Maritime Frontier Dispute (El Salvador/Honduras) – The Nicaraguan Intervention’, (1992) ICLQ 896; A. J. J. de Hoogh, ‘Intervention under Article 62 of the Statute and the quest for incidental jurisdiction without the consent of the principal parties’, (1993) LJIL 739.

⁷ Cf. Land, Island and Maritime Frontier Dispute case, supra note 1, at 135 ff., para. 102 ff.; Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras; Nicaragua intervening), Judgment of 11 September 1992, [1992] ICJ Rep. 610, para. 424.

⁸ Cf. Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria), Application by Equatorial Guinea for permission to intervene, Order of 21 October 1999, [1999] ICJ Rep. 1029; Jurisdictional Immunities of the State (Germany v. Italy), Application by Greece for permission to intervene, Order of 4 July 2011, [2011] ICJ Rep. 494. This conclusion was not questioned in other cases in which the Court dismissed the application due to the failure by the third state to demonstrate the existence of a legal interest capable of being affected by the decision: Sovereignty over Pulau Ligitan and Pulau Sipadan (Indonesia v. Malaysia), Application by the Philippines for permission to intervene, Judgment of 23 October 2001, [2001] ICJ Rep. 575; Territorial and Maritime Dispute (Nicaragua v. Colombia), Applications by Costa Rica and Honduras for permission to intervene, Judgments of 4 May 2011, [2011] ICJ Rep. 348 and 411, respectively.

⁹ See 1978 Rules of the Court, Art. 81.

¹⁰ Ibid.

¹¹ Cf. Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras; Nicaragua intervening), Verbatim Record CR 1991/43, at 40 (emphasis added).

¹² See Rules of the Court, supra note 9.

¹³ Nuclear Tests (Australia v. France), Application by Fiji Islands for permission to intervene, 16 May 1973, available at www.icj-cij.org/public/files/case-related/58/9441.pdf; Nuclear Tests (New Zealand v. France), Application by Fiji Islands for permission to intervene, 18 May 1973, available at www.icj-cij.org/public/files/case-related/59/9455.pdf.

¹⁴ Cf. S. Torres Bernárdez, ‘L’intervention dans la procédure de la Cour internationale de Justice’, (1995) 256 RCADI 193, at 269.

¹⁵ A. Miron and C. Chinkin, ‘Article 62’, in A. Zimmermann et al. (eds.), The Statute of the International Court of Justice. A Commentary (2019), 1686 ff., at 1716 (citations omitted).

¹⁶ See Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras), Application by Nicaragua for permission to intervene, 17 November 1989, available at www.icj-cij.org/en/case/75/intervention, at 4, para. 4 ff.; Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria), Application by Equatorial Guinea for permission to intervene, 27 June 1999, available at www.icj-cij.org/en/case/94/intervention, at 12; Sovereignty over Pulau Ligitan and Pulau Sipadan (Indonesia v. Malaysia), Application by the Philippines for permission to intervene, 13 March 2001, available at www.icj-cij.org/en/case/102/intervention, at 4; Territorial and Maritime Dispute (Nicaragua v. Colombia), Application by Costa Rica, 25 February 2010, available at www.icj-cij.org/en/case/124/intervention, at 10 f., para. 23 ff.; Territorial and Maritime Dispute (Nicaragua v. Colombia), Application by Honduras for permission to intervene, 10 June 2010, available at www.icj-cij.org/en/case/124/intervention, 14 f., para. 33; Jurisdictional Immunities of the State (Germany v. Italy), Application by Greece for permission to intervene, 13 January 2011, available at www.icj-cij.org/en/case/143/intervention, at 10.

¹⁷ Cf. Land, Island and Maritime Frontier case, supra note 1, at 131; Land and Maritime Boundary case, supra note 8, at 1034; Sovereignty over Pulau Ligitan and Pulau Sipadan case, supra note 8, at 604 ff.; Territorial and Maritime Dispute case, supra note 8, at 359 f. and 435 f.; Jurisdictional Immunities case, supra note 8, at 502.

¹⁸ Cf. Morelli (1984), supra note 3, at 406 ff.

¹⁹ Cf. Continental Shelf (Lybia v. Malta) case, supra note 4, at 152 (Sir Robert Jennings, Dissenting Opinion) (emphasis added).

²⁰ In Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras, Nicaragua intervening), though, Nicaragua’s agent, Mr. Arguello Gomez, presented a summary of the position of Nicaragua, which it expressly characterized as ‘formal conclusions’: see Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras, Nicaragua intervening), Verbatim Record CR 1991/49, at 46 f.: ‘We have prepared a sort of summary of the position of Nicaragua in this procedure of intervention which we are exploring; there is nothing very clearly written about it, so we have taken the decision, in accordance with Article 62 of the Statute and Article 85 of the Rules of Court, to present the following, what we have called “formal conclusions”, on behalf of the Republic of Nicaragua.’

²¹ It is accepted, though, that the ‘interest of a legal nature’ justifying intervention under Art. 62 may encompass any state’s right to invoke the responsibility of another state for the breach of an erga omnes obligation: cf. S. Forlati, ‘Azioni dinanzi alla Corte internazionale di giustizia rispetto a violazioni di obblighi erga omnes’, (2001) RDI 69; G. Gaja, ‘The Protection Of General Interests in the International Community. General Course on Public International Law (2011)’, (2013) 364 RCADI 9, at 118 ff. On amicus curiae and its relationship with intervention before the Court see H. Ascensio, ‘L’amicus curiae devant les jurisdictions internationales, (2001) RGDIP 897; P. Palchetti, ‘Opening the International Court of Justice to Third States: Intervention and Beyond’, (2002) UNYB 139; C. Santulli, Droit du contentieux international (2005), 299; G. Gaja, ‘A New Way for Submitting Observations on the Construction of Multilateral Treaties to the International Court of Justice’, in Festschrift Bruno Simma (2011), 665. The Court’s system contemplates certain forms of participation of international organizations as amici curiae in contentious (Arts. 34(2), 34(3), 50, 66 of the Statute; Art. 43(2) of the Rules) and advisory proceedings (Art. 66 of the Statute). Instead, for states the possibility to act as amici curiae is currently contemplated only for advisory proceedings (Art. 66 of the Statute). See ICJ Statute, supra note 2; see Rules of the Court, supra note 9.

²² Cf. Continental Shelf (Tunisia v. Libya) case, supra note 4, at 32, para. 18.

²³ Continental Shelf (Libya v. Malta), ICJ Pleadings, Vol. II (1984), 650.

²⁴ See ICJ Statute, supra note 2.

²⁵ See Territorial and Maritime Dispute (Application by Honduras) case, supra note 8, at 432, paras. 28, 47.

²⁶ See Rules of the Court, supra note 9.

²⁷ Whaling in the Antarctic (Australia v. Japan), Declaration of intervention by New Zealand, Order of 6 February 2013, [2013] ICJ Rep. 9, para. 18; See A. Miron and C. Chinkin, ‘Article 63’, in Zimmermann et al., supra note 15, 1741 ff.; Z. Crespi Reghizzi, ‘L’unità della figura di intervento nello Statuto della Corte internazionale di giustizia’, in Liber amicorum Angelo Davì (2019), 1801 ff.

²⁸ Cf. Continental Shelf (Lybia v. Malta) case, supra note 4, at 18 f., para. 28; Territorial and Maritime Dispute (Application by Honduras), supra note 8, at 435, para. 44.

²⁹ Cf. Monetary Gold Removed from Rome in 1943 (Italy v. France, United Kingdom, and United States of America), Judgment of 15 June 1954, Preliminary question, [1954] ICJ Rep. 19.

³⁰ Cf. C. Rousseau, ‘Le règlement arbitral et judiciaire et les Etats tiers’, in Mélanges H. Rolin (1964) 300, at 307; B. Conforti, ‘L’arrêt de la Cour internationale de justice dans l’affaire de la délimitation du plateau continental entre la Libye et Malte’, (1986) RGDIP 313, at 337; E. Lagrange, ‘Le tiers à l’instance devant les juridictions internationales à vocation universelle (CIJ et TIDM)’, in H. Ruiz-Fabri and M. Sorel (eds.), Le tiers à l’instance devant les juridictions internationales (2005), 9, at 28.

³¹ Cf. Monetary Gold case, supra note 29, at 32.

³² Besides the Monetary Gold case, ibid., see East Timor (Portugal v. Australia), Judgment of 30 June 1995, [1995] ICJ Rep. 90. For further references see A. Zimmermann, ‘Die Zuständigkeit des internationalen Gerichtshofes zur Entscheidung über Ansprüche gegen am Verfahren nicht beteiligte Staaten’, (1995) ZaöRV 1051 ff.; Z. Crespi Reghizzi, L’intervento ‘come non parte’ nel processo davanti alla Corte internazionale di giustizia (2017), at 86 ff.

³³ Cf. E. Jouannet, ‘L’impossible protection des droits du tiers par la Cour internationale de justice dans les affaires de délimitation maritime’, in La mer et son droit: mélanges offerts à Laurent Lucchini et Jean-Pierre Quéneudec (2003), at 315.

³⁴ This method consists of the Court’s avoiding determining the endpoint of the border line and ruling instead that, from a certain point, this line continues along a certain direction until it reaches the area where the rights of third states may be affected. On maps attached to judgments, such result is graphed by a line ending with an arrow: see Maritime Delimitation and Territorial Questions between Qatar and Bahrain (Qatar v. Bahrain), Judgment of 16 March 2001, [2001] ICJ Rep. 116; Land and Maritime Boundary between Cameroon and Nigeria (Cameroon v. Nigeria: Equatorial Guinea intervening), Judgment of 10 October 2002, [2002] ICJ Rep. 449; Territorial and Maritime Dispute between Nicaragua and Honduras in the Caribbean Sea (Nicaragua v. Honduras), Judgment of 8 October 2007, [2007] ICJ Rep. 763; Maritime Delimitation in the Black Sea (Romania v. Ukraine), Judgment of 3 February 2009, [2009] ICJ Rep. 131.

³⁵ Cf. Continental Shelf (Lybia v. Malta), Judgment of 3 June 1985, [1985] ICJ Rep. 25 ff., para. 21 ff., and 56, para. 79.

³⁶ Land and Maritime Boundary case, supra note 34, at 421, para. 238.

³⁷ In Continental Shelf case, the court observed that ‘The rights claimed by Italy would be safeguarded by Article 59 of the Statute.’ See Continental Shelf (Libya v. Malta) case, supra note 4, at 26, para. 42. In Territorial and Maritime Dispute, the court observed that ‘to succeed with its request, Costa Rica must show that its interest of a legal nature in the maritime area bordering the area in dispute between Nicaragua and Colombia needs a protection that is not provided by the relative effect of decisions of the Court under Article 59 of the Statute’. See Territorial and Maritime Dispute (Application by Costa Rica) case, supra note 8, at 372, para. 87.

³⁸ Cf. Continental Shelf (Libya v. Malta) case, supra note 4, at 87, para. 81 (Vice-president Sette-Camara, Dissenting Opinion) and at 157, para. 27 (Sir Robert Jennings, Dissenting Opinion); Territorial and Maritime Dispute (Application by Costa Rica) case, supra note 8, at 378, para. 14 (Judge Al Khasawneh, Dissenting Opinion); ibid., at 411 ff., para. 24 ff. (Judges Cançado Trindade and Yusuf, Dissenting Opinion).

³⁹ Cf. H. Lauterpacht, The Development of International Law by the International Court (1958), at 14; L. Condorelli, ‘L’autorité de la décision des juridictions internationales permanentes’, in La juridiction internationale permanente: colloque de Lyon, Société française pour le droit international (1987), 277; M. Shahabuddeen, Precedent in the World Court (1996) ; N. Miller, ‘An International Jurisprudence? The Operation of “Precedent” Across International Tribunals’, (2002) LJIL 483; Crespi Reghizzi, supra note 32, at 47 ff.

⁴⁰ This was the object of Honduras’s intervention as a party in the Territorial and Maritime Dispute (Nicaragua v. Colombia): see note 69 and accompanying text, infra.

⁴¹ As noted above, Italy’s application to intervene was substantially framed as a non-party intervention.

⁴² See Continental Shelf (Libya v. Malta), Pleadings, Oral Arguments and Documents, Vol. II (1984), at 511 (Monaco).

⁴³ Continental Shelf (Tunisia v. Lybia) case, supra note 4.

⁴⁴ Cf. E. Decaux, ‘L’arrêt de la Cour internationale de justice sur la requête de l’Italie afin d’intervention dans l’Affaire du plateau continental entre la Libye et Malte - arrêt du 21 mars 1984’, (1984) AFDI 282, at 291. The Court did not accept Italy’s position that the object of its intervention would be that of safeguarding its rights, as opposed to asking the Court to recognize them: ‘While formally Italy requests the Court to safeguard its rights, it appears to the Court that the unavoidable practical effect of its request is that the Court will be called upon to recognize those rights, and hence, for the purpose of being able to do so, to make a finding, at least in part, on disputes between Italy and one or both of the Parties.’ The Court hence noted that, if it had admitted Italy to intervene, ‘the Court would be called upon, in order to give effect to the intervention, to determine a dispute, or some part of a dispute, between Italy and one or both of the principal Parties’, which the Court considered impossible, at least in the absence of a jurisdictional link between Italy and the original parties. See Continental Shelf (Tunisia v. Lybia) case, supra note 4, at 19 ff., para. 29 ff.

⁴⁵ Land, Island and Maritime Frontier Dispute case, supra note 1.

⁴⁶ Land and Maritime Boundary between Cameroon and Nigeria case, supra note 8.

⁴⁷ Land and Maritime Boundary between Cameroon and Nigeria case, supra note 8, Written Statement of Equatorial Guinea, 4 April 2001, available at www.icj-cij.org/en/case/94/written-proceedings, at 17, para. 41.

⁴⁸ Land and Maritime Boundary between Cameroon and Nigeria, supra note 8.

⁴⁹ Cf. Territorial and Maritime Dispute (Application by Costa Rica) case, supra note 8, at 368, para. 68 f.

⁵⁰ Cf., ibid., at 378, para. 14 (Judge Al Khasawneh, Dissenting Opinion); ibid., at 411 ff., para. 24 ff. (Judges Cançado Trindade and Yusuf, Dissenting Opinion); ibid., 388 ff., para. 14 ff. (Judge Abraham, Dissenting Opinion); ibid., 416, para. 10 (Judge Donoghue, Dissenting Opinion); ibid., 417, para. 2s (Judge ad hoc Gaja, Declaration). See also S. Forlati, ‘Intervento nel processo ai sensi dell’art. 62 dello Statuto: quale coerenza nella giurisprudenza della Corte internazionale di giustizia?’, (2011) RDI 1197.

⁵¹ Honduras’s claim was instrumental in asserting its rights on the waters outside the Gulf. Unlike El Salvador and Nicaragua, which overlooked both the Gulf and the Pacific Ocean, Honduras overlooks only the Gulf: See Land, Island and Maritime Frontier Dispute, supra note 11, at 52 f. (Brownlie).

⁵² Land, Island and Maritime Frontier Dispute case, supra note 1, at 137. In this judgment, the Court did not authorize Nicaragua’s intervention with respect to the delimitation of the waters of the Gulf of Fonseca, the legal situation of the maritime spaces outside the Gulf, and the legal situation of the islands in the Gulf.

⁵³ Cf. Land, Island and Maritime Frontier Dispute, supra note 11, at 64 (Brownlie) (emphasis added). See also the conclusions of Nicaragua’s agent Mr. Carlos Arguello Gomez, ‘Without prejudice to the above, there are substantial considerations of judicial propriety on the basis of which Honduran maritime claims, which form part of the submissions relating to a community of interests, should be treated as inadmissible’ (emphasis added). Land, Island and Maritime Frontier Dispute, supra note 20, at 47.

⁵⁴ On this possibility the case law provides conflicting indications, and the opinions of legal authors are divided. For further analysis, see Crespi Reghizzi, supra note 32, at 365 ff.

⁵⁵ Cf. Section 2.2, infra.

⁵⁶ For this terminology see B. I. Bonafè, ‘Interests of a legal nature justifying intervention before the ICJ’, (2012) LJIL 739, at 750 ff.

⁵⁷ Cf. supra note 39 and accompanying text.

⁵⁸ Cf. Section 2, supra.

⁵⁹ Cf. Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras; Nicaragua intervening), Written statement of Nicaragua, 14 December 1990, available at www.icj-cij.org/en/case/75/written-proceedings, 11 ff. See Land, Island and Maritime Frontier Dispute, supra note 11, at 10 (Arguello Gomez); Land, Island and Maritime Frontier Dispute, Supra note 20, at 12 ff. (Brownlie) and at 47 (Arguello Gomez).

⁶⁰ In application for permission to intervene by the Philippines, it was stated that ‘The interest of the Republic of the Philippines is solely and exclusively addressed to the treaties, agreements and other evidence furnished by Parties and appreciated by the Court which have a direct or indirect bearing on the matter of the legal status of North Borneo.’ See Sovereignty over Pulau Ligitan and Pulau Sipadan, supra note 16, at 4, para. 4.

⁶¹ Cf. Sovereignty over Pulau Ligitan and Pulau Sipadan case, supra note 8, at 596, para. 47.

⁶² S. Forlati, ‘“Interesse di natura giuridica” ed effetti per gli Stati terzi delle sentenze della Corte internazionale di giustizia’, (2002) RDI 99.

⁶³ Cf. Jurisdictional Immunities of the State (Germany v. Italy), Observations of Greece in reply to the Written Observations of Germany and Italy, 4 May 2011, available at www.icj-cij.org/en/case/143/written-proceedings, para. 7 (translation).

⁶⁴ Cf. Jurisdictional Immunities of the State (Germany v. Italy, Greece intervening), Written Statement of the Hellenic Republic, 3 August 2011, available at www.icj-cij.org/en/case/143/written-proceedings, at 20, para. 63; Jurisdictional Immunities of the State (Germany v. Italy, Greece intervening), Verbatim Record, CR 2011/19, at 43, para. 128 (Perrakis).

⁶⁵ Cf. Jurisdictional Immunities of the State (Germany v. Italy, Greece intervening), Written Observations of Germany on the Written Statement of Greece, para. 2 ff.

⁶⁶ Sovereignty over Pulau Ligitan and Pulau Sipadan, supra note 16, at 2, para. 2 (emphasis added).

⁶⁷ Jurisdictional Immunities of the State, supra note 16, at 10 (emphasis added).

⁶⁸ Cf. E. J. Cohn, ‘Parties’, in International Encyclopedia of Comparative Law, Vol. XVI, Ch. 5 (1974), 56.

⁶⁹ Territorial and Maritime Dispute (Nicaragua v. Colombia), Application by Honduras for permission to intervene, 10 June 2010, available at www.icj-cij.org/en/case/124/intervention, 10, para. 21 ff.

⁷⁰ Cf. Section 2.1, supra.

⁷¹ Cf. the map reproduced in the Territorial and Maritime Dispute (Application by Costa Rica) case, supra note 8, at 366.

⁷² See Territorial and Maritime Dispute, supra note 8, at 388 (Judge Abraham, Dissenting opinion); P. Jacob, ‘L’intervention devant la Cour internationale de Justice à la lumière des décisions rendues en 2011: lente asphyxie ou résurrection’, (2011) 213 AFDI, at 221.

⁷³ See Territorial and Maritime Dispute, supra note 8, at 441. Within this area, Honduras claimed to have certain sovereign rights such as oil concessions, naval patrols, and fishing activities: See Territorial and Maritime Dispute, supra note 8, at 437, para. 50.

⁷⁴ Cf. Territorial and Maritime Dispute between Nicaragua and Honduras case, supra note 34, at 659.

⁷⁵ Cf. Territorial and Maritime Dispute, supra note 8 (Judges Abraham and Donoghue, Dissenting opinions), [2011] ICJ Rep. 456, para. 35, and 487, para. 45, respectively; Jacob, supra note 72, at 221.

⁷⁶ Territorial and Maritime Dispute (Application by Honduras) case, supra note 8, at 443 f., para. 71.

⁷⁷ It is undisputed that, when a third state is permitted to intervene as a party to the proceedings, the Court’s decision ‘would be binding for that State in respect of those aspects for which intervention was granted, pursuant to Article 59 of the Statute’: See Territorial and Maritime Dispute, ibid., at 432, para. 29.

⁷⁸ Art. 62 also differs from Art. 31(3) of the ITLOS Statute, which provides that: ‘If a request to intervene is granted, the decision of the Tribunal in respect of the dispute shall be binding upon the intervening State Party in so far as it relates to matters in respect of which that State Party intervened.’

⁷⁹ See Land, Island and Maritime Frontier Dispute supra note 7, at 610, para. 424.

⁸⁰ Ibid., at 609 f., para. 423 f.

⁸¹ See Land, Island and Maritime Frontier Dispute, supra note 7, ibid.

⁸² Cf. Land, Island and Maritime Frontier Dispute (El Salvador v. Honduras; Nicaragua intervening) case, supra note 7, at 619 f. (Vice-President Oda, Declaration); and at 730 f., para. 208 (Judge ad hoc Torres Bernárdez, Separate Opinion).

⁸³ Cf. S. Oda, ‘Intervention in the International Court of Justice. Articles 62 and 63 of the Statute’, in R. Bernard et al. (eds.), Völkerrecht als Rechtsordnung, internationale Gerichtsbarkeit, Menschenrechte. Festschrift für Hermann Mosler (1983), 629, at 644; C. Chinkin, ‘Third-Party Intervention before the International Court of Justice’, (1986) AJIL 495, at 526; Torres Bernárdez, supra note 14, at 436; D. W. Greig, ‘Third Party Rights and Intervention before the International Court’ [1991–1992] Virginia JIL 285, at 326 ff.; L. Caflisch, ‘Cent ans de règlement pacifique des différends interétatiques’, (2001) 288 RCADI 245, at 405 f.; Santulli, supra note 21, at 302 f.; R. Kolb, The International Court of Justice (2013), 720, 728; S. Forlati, The International Court of Justice. An Arbitral Tribunal or a Judicial Body? (2014), at 200. For the opposite conclusion, cf. J. M. Ruda, ‘Intervention before the International Court of Justice’, in V. Lowe and M. Fitzmaurice (eds.), Fifty Years of the International Court of Justice. Essays in Honour of Sir Robert Jennings (1996), 487, at 501; C. E. Amerasinghe, Jurisdiction of International Tribunals (2003), 327 f.; Palchetti, supra note 21, at 154 f.; M. Al-Qahtani, ‘The Status of Would-Be Intervening States before the International Court of Justice and the Application of Res Judicata’, (2003) 269 LPICT, at 284; G. Cellamare, ‘Corte internazionale di giustizia’, in Enciclopedia del diritto, Annali, Vol. V (2012) 421, at 455. In doubtful terms, cf. S. Rosenne, Intervention in the International Court of Justice (1993), 155; M. Shaw, Rosenne’s Law and Practice of the International Court: 1920-2015 (2016), 1556 f.; J. J. Quintana, Litigation at the International Court of Justice. Practice and Procedure (2015), 903 ff.

⁸⁴ See, for instance, Territorial and Maritime Dispute; cf. supra note 69 and accompanying text.

⁸⁵ Cf. Section 2, supra.

⁸⁶ Cf. Section 2.1, supra.

⁸⁷ Cf. Section 2.2, supra.

⁸⁸ Cf. Section 2.3, supra.

⁸⁹ Greig, supra note 83, at 326. See also Chinkin, supra note 83, at 526; Torres Bernárdez, supra note 14, at 436; Santulli, supra note 21, at 302. f.

⁹⁰ Cf. Institut de droit international, Resolution of 24 August 1999 on judicial and arbitral settlement of international disputes involving more than two states, Annuaire IDI, Vol. 68-II, 376, Art. 17: ‘The decision of the court or tribunal is binding on the intervening State to the extent of the admitted intervention. To the same extent, the decision is binding on the principal parties in their relations with the intervening State.’

⁹¹ See ICJ Statute, supra note 2, Art. 63.

⁹² Cf. Whaling in the Antarctic case, supra note 27, at 9, para. 18.

⁹³ Cf. Greig, supra note 83, at 333; B. I. Bonafè, La protezione degli interessi di Stati terzi davanti alla Corte internazionale di giustizia (2014), 57.

⁹⁴ Land, Island and Maritime Frontier case, supra note 7, at 730 f., para. 208 (Judge ad hoc Torres Bernárdez, Separate Opinion).

⁹⁵ Cf. Kolb, supra note 83, at 720. During the preliminary session of the Court in 1922 (CPJI, Série D, n. 2, 349, para. 3), Judge Beichmann summarized the debate as follows: ‘La question de savoir si, l’intervention ayant été admise et effectuée, l’Etat intervenant sera lié par la sentence de même que les parties originaires doit également rester ouverte.’

⁹⁶ Cf. Interpretation of Judgments Nos. 7 and 8 (Factory at Chorzów) (Germany v. Poland), Judgment of 16 December 1927, PCIJ Rep Series A No 13, 4 ff., at 20; Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro), Judgment of 26 February 2007, [2007] ICJ Rep. 43 ff., at 99, para. 133; Request for Interpretation of the Judgment of 15 June 1962 in the Case concerning the Temple of Preah Vihear (Cambodia v. Thailand), Judgment of 11 November 2013, [2013] ICJ Rep. 281 ff., at 296, para. 34. This conclusion, though, is widely debated among legal authors: in particular cf. G. Gaja, ‘Considerazioni sugli effetti delle sentenze di merito della Corte internazionale di giustizia’, XIV Comunicazioni e studi 313 (1975); R. Bernhardt, ‘Article 59’, in A. Zimmermann et al., supra note 15, at 1231; Kolb, supra note 83, at 767.

⁹⁷ A third state that does not intervene, however, is subject to the persuasive authority of international judgments (and notably judgments of the Court) in determining rules and principles of international law: see supra note 39 and accompanying text.

⁹⁸ Of course, the binding effects for the third state only concern the judicial interpretation of the convention, with the exclusion of any further aspect of the main dispute.

⁹⁹ Cf. E. Hambro, ‘The reasons behind the decisions of the International Court of Justice’, (1954) 212 Current Legal Problems, at 217 f.

¹⁰⁰ Cf. Section 2, supra.

¹⁰¹ Cf. Section 2.1, supra.

¹⁰² For the sake of completeness, a third state that has a jurisdictional link towards the original parties could – at least theoretically – also intervene as a party and ask the Court to adjudicate on its own claims over the areas concerned by the original parties’ claims. See, for instance, Honduras’s application to intervene in the Territorial and Maritime Dispute (Nicaragua v. Colombia), supra note 69, and accompanying text. As explained above (see supra note 84 and accompanying text), in this scenario the judgment is res judicata on the intervener as any other judgment deciding on the parties’ claims. The following analysis does not address this scenario.

¹⁰³ See supra note 39 and accompanying text.

¹⁰⁴ Cf. Torres Bernárdez, supra note 14, at 266: ‘L’intervention, toujours volontaire, du tiers, pourrait, dans ce type de situation particulière, mitiger d’une façon indirecte les effets négatifs dont nous avons fait état dans la mesure où la Cour disposerait alors d’une information plus précise, fournie par le tiers lui-même, sur ses intérêts d’ordre juridique en cause dans l’affaire, ce qui lui permettrait de mieux apprécier si, effectivement, ces intérêts risquent non seulement d’être affectés par sa décision dans le litige, mais constituent l’objet même de ladite décision.’ See also G. Sperduti, ‘Notes sur l’intervention dans le procès international, in Le droit international à l’heure de sa codification. Etudes en l’honneur de Roberto Ago, Vol. III (1987) 429, at 435 f.; Jacob, supra note 72, at 220.

¹⁰⁵ Cf. G. Fitzmaurice, ‘The Law and Procedure of the International Court of Justice, 1951–4: Questions of Jurisdiction, Competence and Procedure’, (1958) BYBIL 1, at 126; Shaw, supra note 83, 1638, note 207; Greig, supra note 83, at 334; Palchetti, supra note 21, at 150 f.

¹⁰⁶ Land and Maritime Boundary case, supra note 34, at 457, para. 325.IV.D

¹⁰⁷ Ibid., at 448, para. 307.

¹⁰⁸ Cf. Oda, supra note 83, at 644 (emphasis added). See also Kolb, supra note 83, at 720.

¹⁰⁹ Cf. Continental Shelf (Lybia v. Malta), ICJ Pleadings, Vol. II, at 512 f., para. 10f. (emphasis added).

¹¹⁰ Cf. Section 2.2, supra.

¹¹¹ Cf. Section 3, supra.

¹¹² Cf. Jurisdictional Immunities of the State (Germany v. Italy: Greece intervening), Judgment of 3 February 2012, [2012] ICJ Rep. 139, para. 91.

¹¹³ Greece actively participated to the discussion on this point: see Section 2.2, supra.

¹¹⁴ Cf. Section 3, supra.

¹¹⁵ Land, Island and Maritime Frontier Dispute, supra note 7, at 269.

¹¹⁶ Cf. Land, Island and Maritime Frontier case, supra note 7, at 619 f. (Vice-President Oda, Declaration); and at 730 f., para. 208 (Judge ad hoc Torres Bernárdez, Separate Opinion).

¹¹⁷ Between El Salvador and Nicaragua, this issue had already been determined with res judicata effect by a judgment of 9 March 1917 of the Central American Court of Justice, which reached the same conclusion: (1917) AJIL 674.

¹¹⁸ Cf. Section 2.3, supra.

¹¹⁹ This outcome shows a certain analogy with the regime of ‘dependant’ intervention in domestic systems of civil procedure. For instance, under Art. 68 of the German Code of Civil Procedure, following intervention as ‘dependent intervener’ (i.e., in support of one of the parties, ‘Nebenintervention’), a third party is precluded from asserting against the supported party that the dispute forming the subject matter of the main proceedings, as presented to the judge, was decided incorrectly.

¹²⁰ Territorial and Maritime Dispute (Nicaragua v. Colombia), Judgment of 19 November 2012, [2012] ICJ Rep. 624.

¹²¹ Ibid.; cf. S. Forlati, ‘Delimitazione dei confine marittimi e Stati terzi: il caso Nicaragua c. Colombia’, (2013) RDI 135.

¹²² See Territorial and Maritime Dispute between Nicaragua and Honduras case, supra note 34, at 659. See Section 2.3, supra.

¹²³ See Territorial and Maritime Dispute, supra note 120.

¹²⁴ See Territorial and Maritime Dispute, supra note 34.

¹²⁵ Cf. supra, note 69 and accompanying text.