11 Read through the lens of the theoretical tool of obligations erga omnes, it seems that the concept, if not the notion of actio popularis, had already been employed by the Permanent Court of International Justice (‘PCIJ’) in its very first judgment in the S.S. Wimbledon case in 1923. Contrary to the express provision of Article 380 Versailles Treaty, Germany had closed the passage of the Kiel Canal to a vessel under British flag and chartered by a French company. The suits against Germany were initiated not only by the United Kingdom and by France but also by Italy and Japan. The two latter States had apparently no individual interest in the dispute. Germany drew the attention of the Court to the point but did not raise a formal objection. In their reply the four applicants argued that they all were ‘interested in the respect of the principle of free passage through the Kiel Canal and to the exact execution of the clauses of the Versailles Treaty’ (S.S. Wimbledon, 1923, 65). For its part the PCIJ dealt with the locus standi of the applicant States and found that ‘each of the four Applicant Powers has a clear interest in the execution of the provisions relating to the Kiel Canal, since they all possess fleets and merchant vessels flying their respective flags’ (S.S. Wimbledon, 20). It is apparent that the Court gave the broadest interpretation to the requirement of ‘interest’ contained in Article 386 Versailles Treaty.
12 On the contrary, the jurisprudence of the ICJ started from a strict bilateralist perspective. In the Advisory Opinion on the Bernadotte case of 1949 the Court affirmed that ‘only the parties to whom the international obligation is due can bring a claim in respect of its breach’ (Reparation for Injuries Suffered in the Service of the United Nations, Advisory Opinion, 1949, 181–82). Nevertheless, shortly after, in the Advisory Opinion on Reservations to the Genocide Convention of 1951, the Court recognized the existence of common interests, and expressly said that in such a Convention ‘the Contracting States do not have any interests of their own; they merely have, one and all a common interest’ (Reservations to the Convention on the Prevention and Punishment of the Crime of Genocide, Advisory Opinion, 1951, 23). Although the two sentences stand in no contradiction to each other, the second one somehow subdues the rigor of the first, because it implies that, under certain circumstances, the applying State must not prove an individual legal interest in instituting judicial proceedings.
13 The first and to date only mention of the notion of actio popularis as such was made by the International Court of Justice in the second phase of the South-West Africa case in 1966, but in order to dismiss the request by Ethiopia and Liberia, by denying their legal interest to sue South Africa for the violation of Article 22 Statute of the League of Nations. On that occasion the Court, by the casting vote of the President, denied that the concept was known in international law ‘as it stands at present’. Furthermore, the Court refused to regard it ‘as imported from the general principles of law referred to in Article 38, para. 1 lett c) of its Statute’ (South West Africa, 47, para 88). The two branches of the sentence led some interpreters to read in the Court’s position a definite, if contested, preclusion of the very possibility of such a concept ever entering the realm of international law (Seidl-Hohenveldern, 1975, 806, with the argument that a true actio popularis presupposes a compulsory jurisdiction). Others saw in the dictum of the Court a too ‘sweeping assertion’, which needed to be qualified by the relevant facts of the case, ie by the interpretation which the Court had given to the jurisdictional clause contained in Article 7 Covenant of the League of Nations (Gowland-Debbas, 1997, 353). Others observed that the function, if not the notion of actio popularis, was not unknown in the jurisprudence of the Court’s predecessor, the Permanent Court of International Justice, in such cases as the already mentioned Wimbledon (1923), Certain Interests in Polish Upper Silesia (1925), or Interpretation of the Statute of the Memel Territory (1932), even if in those cases the right to action was expressly provided for in the compromissory clauses of the relevant treaties (Tams, 2005, 77 et seq).
14 As has been already said, such a radical rejection of actio popularis, if indeed ever intended by the Court, was nevertheless reversed in the subsequent Barcelona Traction decision of 1970, in which the Court introduced the concept of obligations erga omnes, (Barcelona Traction, Light and Power Company, Limited, Belgium v Spain, 1970, 32, para 33). The introduction of the concept overturned for all practical purposes the previous denial of actio popularis. Provided that the Court has a basis of jurisdiction, in a dispute concerning an erga omnes obligation, the legal interest of the Applicant State to sue is considered in re ipsa (see however for a contrary, even if cursorily stated view, Lachs, 1980, 341, for whom ‘there is a long way from the dictum of the Court to actio popularis’).
15 To date only nine cases involving obligations erga omnes have been brought to the attention of the ICJ. Only in four instances was the Court able to reach a (positive) decision on admissibility. The first case was the dispute between Portugal and Australia concerning East Timor. In its decision of 1995 the ICJ recognized the right of self-determination as an obligation erga omnes and for that reason it recognized the legal interest of Portugal to sue Australia for the alleged violation of such a right, ensuing from the exploitation of the natural resources of the Timor Gap. Nevertheless, the Court refused to exercise its jurisdiction, as a consequence of the doctrine of the ‘necessary third party’ (Case Concerning East Timor, Portugal v Australia, 1995, 102, para 29) (Indispensable Party).
17 The third case was the counterclaim by Uganda against the Democratic Republic of Congo (‘DRC’) in the dispute concerning military activities in the territory of the DRC of 2005. The Court admitted the counterclaim but only for the injury suffered by the individuals, in regard of whom Uganda had been able to prove the link of citizenship. Even if the Court did not mention it, this position seems to find a precedent in the Barcelona Traction decision of 1970. In that case the Court, after having introduced at paragraph 34 the concept of erga omnes obligations, at paragraph 91 made the statement that ‘on the universal level, the instruments which embody human rights do not confer on States the capacity to protect the victims of infringements of such rights irrespective of their nationality’. Legal literature had variously tried to explain away that apparent contradiction, for instance by making the distinction between genuinely universal human rights like the prohibition of genocide, slavery, and egregious violations of fundamental human rights on the one side, and human rights in general on the other side. It seems, though, that the best explanation for the apparent contradiction is to be sought in an unfortunate formulation on the part of the Court, which in that paragraph meant to distinguish the aspect of the legal interest to act from the one of its jurisdictional basis (Voeffray, 2004, 77; Tams, 2010, 196). At any rate, the decision of the Court in the Military Activities case was criticized in the separate opinion of Judge Simma, who deplored the missed opportunity by the Court to reinforce the erga omnes character of humanitarian law, in particular of the rules on the protection of civilians in the course of an armed conflict (Armed activities on the Territory of the Congo, Democratic Republic of Congo v Uganda, 2005, Opinion of Judge Simma, 334).
20 The sixth case was the 2012 Whaling in the Antarctic dispute between Australia and Japan, with New Zealand intervening. In its application of 31 May 2010, Australia sued Japan, lamenting the violation of Article 8 International Convention on the Regulation of Whaling (‘ICRW’). The basis of jurisdiction of the Court was the unilateral declarations rendered by the parties under Article 36 (2) ICJ Statute. Japan objected to the jurisdiction of the Court by virtue of a reservation by Australia relating to disputes concerning ‘the exploitation of any disputed area of or adjacent to any such maritime zone pending its delimitation’. However it did not raise the question of Australia’s legal interest, implicitly assuming such interest from the fact that Australia advances sovereign rights over a part of the Antarctic waters in which Japan deployed its activities. The objections on jurisdiction were dismissed by the ICJ, but the Court itself did not enter either into the question of Australia’s legal interest, implicitly acknowledging the erga omnes partes character of the ICRW (Whaling in the Antarctic, Australia v Japan: New Zealand Intervening, 2014, 251, para 56).
21 The three final cases concern alleged obligations of negotiations relating to the cessation of the nuclear arms race and to nuclear disarmament. In 2014 the Marshall Islands brought nine distinct applications against the nine States in possession of nuclear weapons, but six of the applications were struck off the list for manifest lack of jurisdiction. For the three remaining cases against India, Pakistan, and the United Kingdom, the ICJ’s jurisdiction was based on the optional clause under Article 36 (2) ICJ Statute. In their applications, the Marshall Islands clearly drew their legal standing from the erga omnes character of the customary international law obligation to negotiate a comprehensive nuclear arms ban reflected in Article VI Non Proliferation Treaty of 1968. In all three cases the Court did not express an opinion on the point, because it upheld the first preliminary objection by the respondent States on the lack of a dispute between the parties (Obligations concerning Negotiations relating to Cessation of the Nuclear Arms Race and to Nuclear Disarmament, Marshall Islands v India, 2016, 266, para 25 et seq; Obligations concerning Negotiations relating to Cessation of the Nuclear Arms Race and to Nuclear Disarmament, Marshall Islands v Pakistan, 2016, 563, para 25 et seq; Obligations concerning Negotiations relating to Cessation of the Nuclear Arms Race and to Nuclear Disarmament, Marshall Islands v United Kingdom, 2016, 846, para 26 et seq).
22 As a whole, it is difficult to draw from the ICJ jurisprudence a clear-cut answer as to the actual place of actio popularis. Of the four cases judged admissible so far, two (Belgium v Senegal and Australia v Japan) concerned obligations erga omnes partes. The only cases truly concerning obligation erga omnes of customary nature were the Serbian counterclaims in the Genocide cases, but there the legal interest of Serbia as parens patriae was manifest, given the ethnicity of the population concerned. In order to both overcome the hurdles linked to the rules of standing and to make an actio popularis politically more palatable for States, in international legal literature the suggestion was made to relax the requirements for third party intervention identified by the Court’s jurisprudence both under Article 62 ICJ Statute in general (Bonafé, 2012, 754 et seq) and under Article 63 ICJ Statute with specific regard to the construction of a multilateral treaty (Gaja, 2011, 669).