1. The perplexing legacy of LaGrand
Under Article 41 of its Statute, the International Court of Justice (ICJ or the Court) has ‘the power to indicate, if it considers that circumstances so require, any provisional measures which ought to be taken to preserve the respective rights of either party’.Footnote 1 According to the established test for indicating provisional measures, developed by way of its jurisprudence, the Court may exercise the power under Article 41 if four requirements are met: i) the Court has prima facie jurisdiction over the merits of the case; ii) there is a risk of irreparable prejudice to the rights of the applicant state; iii) there is urgency in the circumstances; and iv) there is a link between the provisional measures requested and the rights whose protection is sought.Footnote 2 However, the Court introduced a fifth requirement in its 2009 order in Belgium v. Senegal, when it held that ‘the power . . . to indicate provisional measures should be exercised only if the Court is satisfied that the rights asserted by a party are at least plausible’.Footnote 3
The Court referred to concepts similar to plausibility in the two 1973 orders in Nuclear Tests Footnote 4 and in the order of 13 September 1993 in Bosnian Genocide.Footnote 5 Judge Shahabuddeen wrote on a concept comparable to plausibility in his 1991 separate opinion in Passage through the Great Belt.Footnote 6 However, the debate on plausibility intensified after the 2001 LaGrand judgment, in which the Court found that ‘orders on provisional measures under Article 41 have binding effect’.Footnote 7 Plausibility as adopted by the Court originated from the separate opinion appended by Judge Abraham to the 2006 order on provisional measures in Pulp Mills.Footnote 8 Judge Abraham stated that the Court:
cannot order a State to conduct itself in a certain way simply because another State claims that such conduct is necessary to preserve its own rights, unless the Court has carried out some minimum review to determine whether the rights thus claimed actually exist and whether they are in danger of being violated . . . Footnote 9
The Court has assessed plausibility in all orders on provisional measures since Belgium v. Senegal.Footnote 10 Although judges have commented on plausibility in their individual opinions, the Court has not yet fully elaborated on the plausibility test. In 2011, Judge Koroma wrote that ‘the most problematic aspect of the plausibility standard is its vagueness’,Footnote 11 and Judge Sepúlveda-Amor raised the ‘urgent need to define with greater precision the applicable legal standard for [plausibility]’.Footnote 12 Nine years have passed since Belgium v. Senegal, but few commentators have written on plausibility.Footnote 13 This article argues that plausibility, originally adopted by the Court as a test only aimed at establishing whether applicant states might hold the rights they assert under international law, has evolved into a higher standard also aimed at establishing whether the conduct of respondent states might breach the applicant states’ asserted rights.
Although this article focuses on provisional measures indicated under Article 41 of the ICJ's Statute, issues of plausibility also arise in provisional measures before international courts and tribunals other than the ICJ. In its 2015 order in Ghana/Côte d'Ivoire,Footnote 14 the Special Chamber of the International Tribunal for the Law of the Sea held that plausibility is a requirement for prescribing provisional measures under Article 290 of the 1982 United Nations Convention on the Law of the Sea (UNCLOS).Footnote 15 In 2011, the Indus Waters Kishenganga Court of Arbitration interpreted paragraph 28 of Annexure G to the 1960 Indus Waters TreatyFootnote 16 to entail that, in order to lay down provisional measures, ‘the Court must be satisfied that . . . the claims set forth by the Party seeking interim measures appear to be at least “plausible”’.Footnote 17 Certain arbitral tribunals recommending provisional measures under Rule 39 of the ICSID Rules of Procedure have adopted the plausibility test, yet the exact plausibility standard remains unclear.Footnote 18 Arbitral tribunals may grant provisional measures under the 2010 UNCITRAL Arbitration Rules only if ‘[t]here is a reasonable possibility that the requesting party will succeed on the merits of the claim’.Footnote 19 The ICJ's approach to the plausibility test could affect its formulation and application by other international courts and tribunals.
Section 2 reviews the development of plausibility in the Court's jurisprudence. Section 3 examines the implications of this development with respect to the components of the plausibility test, the character of the rights asserted on the merits, the overlap between plausibility and prima facie jurisdiction, and provisional measures requested in interpretation proceedings. Section 4 articulates some key principles relating to plausibility suggested by the Court's jurisprudence.
2. The development of plausibility in the Court's jurisprudence
Plausibility appeared in the ICJ's provisional measures jurisprudence before its adoption in the 2009 order in Belgium v. Senegal. Subsequently, the Court developed plausibility into a higher standard than the one originally adopted.
2.1. The origins of plausibility: Judge Abraham's separate opinion in Pulp Mills
In Pulp Mills, Argentina sought to protect its rights under the 1975 Statute of the River UruguayFootnote 20 by requesting the Court to indicate that Uruguay should suspend all authorizations relating to the construction of certain mills.Footnote 21 In its order of 13 July 2006, the Court rejected Argentina's request as ‘the circumstances . . . [were] not such as to require the exercise of [the] power under Article 41 of the Statute to indicate provisional measures’.Footnote 22 Although they both voted with the majority, Judges Abraham and Bennouna wrote separate opinions stating that the Court should have examined the existence of the rights asserted by Argentina.Footnote 23
Judge Abraham's separate opinion focused both on the raison d’être of plausibility, and on the standard for its assessment. On the former, he wrote that:
[a]ccording to a widespread view . . . the Court, when called upon to rule on a request for the indication of provisional measures under Article 41 of the Statute, should . . . proceed on the basis that the claimed rights do in fact exist and it should consider solely whether, on the assumption that it will ultimately uphold them in its decision on the merits, they are liable to be violated in the interim in such way that the final judgment will be rendered ineffective, at least in part.Footnote 24
On the standard for assessing plausibility, Judge Abraham wrote that ‘it is neither possible nor desirable for the Court to develop a firm opinion about the case, let alone to express one, during the [provisional measures] phase of the proceedings’.Footnote 25 However, ‘in conducting some review . . . of the prima facie validity of the requesting party's case, the Court does not overstep the bounds of its mission as a jurisdiction appealed to for interim relief’.Footnote 26Judge Abraham seemed to consider it sufficient for the applicant state to show that the right it asserts ‘is not patently non-existent’ under international law, and that the respondent state's ‘conduct infringing that right is not manifestly to be ruled out’.Footnote 27 He also mentioned a higher plausibility standard, under which the applicant state should establish ‘a particular degree of probability that it holds the right claimed and a particular degree of probability that the right is likely to be infringed through the other party's conduct’.Footnote 28 However, Judge Abraham did not take a definitive position in this respect, which might have influenced the subsequent development of the plausibility test.Footnote 29
2.2. The adoption and development of the plausibility test by the Court
In the 2009 order in Belgium v. Senegal, the Court adopted a plausibility test aimed at assessing the plausibility of the applicant state's asserted rights. Subsequently, the Court developed plausibility into a higher standard, focused on establishing the plausibility both of the applicant state's asserted rights, and of the applicant state's claims on the merits of the case.Footnote 30
2.2.1. Assessing plausibility in respect of rights (2009–2014)
In Belgium v. Senegal, Belgium alleged that Senegal had breached its obligations arising under the 1984 Torture ConventionFootnote 31 by failing to prosecute Chad's former head of state, Hissène Habré, who was residing in Senegal.Footnote 32 Belgium argued that the Torture Convention ‘confers upon all the States parties the right to obtain compliance . . . with [its] provisions’,Footnote 33 and that Belgium's ‘request for the extradition of Mr. Habré . . . confers a specific right upon it to see Senegal prosecute Mr. Habré or, failing that, to obtain his extradition in accordance with Article 7 of the [Torture Convention]’.Footnote 34 Senegal contended that, ‘if it is considered that . . . Article 7, paragraph 1, of the [Torture Convention] create[s] a right for a State party, it can only be the right to demand extradition’.Footnote 35
The Court found that ‘at this stage of the proceedings [it] does not need to establish definitively the existence of the rights claimed by Belgium or to consider Belgium's capacity to assert such rights before the Court’.Footnote 36 It held that ‘the rights asserted by Belgium, being grounded in a possible interpretation of the [Torture Convention], . . . appear to be plausible’.Footnote 37 The Court focused on the plausible existence of Belgium's asserted rights, as suggested by the fact that its findings were limited to establishing that Belgium's rights were ‘grounded in a possible interpretation’ of the Torture Convention.
In the 2011 provisional measures proceedings in Certain Activities, Costa Rica's asserted rights were ‘sovereignty over the entirety of Isla Portillos and over the Colorado River’Footnote 38 under the 1858 Treaty of Limits,Footnote 39 and the ‘right to protect the environment in those areas over which [Costa Rica] is sovereign’ under customary international law.Footnote 40 Concerning the latter, the Court found that its legal basis might be paragraph 6 of the third clause of the 1888 Cleveland Award.Footnote 41 With respect to the former, the Court simply stated that ‘the title to sovereignty claimed by Costa Rica over the entirety of Isla Portillos is plausible’.Footnote 42 The Court only enquired into whether Costa Rica's asserted rights had a plausible legal basis under international law. In 2013, Costa Rica requested the Court to indicate further provisional measures in Certain Activities.Footnote 43 In its order of 22 November 2013, the Court upheld its 2011 finding that Costa Rica's sovereignty over Isla Portillos was plausible, as there was ‘no reason to depart from this conclusion’.Footnote 44 The Court also stated that Costa Rica's asserted right to environmental protection was plausible, its legal basis being that ‘future environmental harm caused in the disputed territory would infringe Costa Rica's alleged territorial rights’.Footnote 45
In its order of 13 December 2013 in Construction of a Road, the Court confirmed the plausibility test as previously applied. Nicaragua sought to protect rights comparable to those asserted by Costa Rica in Certain Activities: sovereignty over Isla Portillos under the 1858 Treaty of Limits, the right to be free from transboundary harm, and the ‘right to receive a transboundary environmental impact assessment from Costa Rica’ under customary international law.Footnote 46 Following its previous orders in Certain Activities, the Court held that Nicaragua's right to sovereignty over Isla Portillos was plausible under the 1858 Treaty of Limits. Concerning the right to be free from transboundary harm, the Court found it to be plausible as it ‘derived from the right of a State to sovereignty and territorial integrity’.Footnote 47 The Court also held that Nicaragua's right to receive an environmental impact assessment from Costa Rica was plausibly based on a customary rule of international law which the Court had found to exist in its 2010 Pulp Mills judgment.Footnote 48 Although the Court did not further comment on plausibility, it seemed to adopt the same standard applied in its earlier orders by examining whether Nicaragua's asserted rights had a plausible legal basis under international law.
Certain Documents and Data concerned the seizure and detention by Australia of Timor-Leste's property originally in the possession of Timor-Leste's counsel and relating to the on-going arbitration under the Timor Sea Treaty.Footnote 49 Timor-Leste sought to protect two distinct rights under customary international law: ‘the ownership and property rights which it holds over the seized material . . . and its right to the confidentiality of communications with its legal advisers’.Footnote 50 However, in its 2014 order the Court only addressed whether the latter right was plausible, and found that it could be ‘derived from the principle of the sovereign equality of States’.Footnote 51 The Court focused on establishing whether one of the rights asserted by Timor-Leste had a plausible legal basis under international law, thus confirming the approach adopted in the previous cases. The focus on one of the two rights asserted by Timor Leste could suggest the Court's inclination only to apply the plausibility test to the right or rights which might satisfy the test more easily. This approach would emphasize the Court's discretion. Moreover, applicant states could feel encouraged to request provisional measures with respect to a number of arguably plausible rights, knowing that the Court might cherry-pick in its assessment of plausibility. Nevertheless, such consequences appear unlikely, since Certain Documents and Data is the sole instance in which the Court did not assess plausibility in respect of all the rights invoked by an applicant state.
2.2.2. Assessing plausibility in respect of claims (2016–present)
The Court's approach to plausibility seemed to evolve in the 2016 order in Immunities and Criminal Proceedings. Equatorial Guinea argued that France had breached Article 22 of the 1961 Vienna Convention on Diplomatic Relations (VCDR)Footnote 52 by attaching its alleged diplomatic premises located at 42 avenue Foch, Paris. The Court held that ‘the right to the inviolability of diplomatic premises is a right contained in Article 22 [VCDR]’.Footnote 53 However, for the first time the Court also made findings of fact. It noted that:
Equatorial Guinea claims that it has used the building in question as premises of its diplomatic mission in France since 4 October 2011, and that France acknowledges that, from the summer of 2012, certain services of the Embassy of Equatorial Guinea appear to have been transferred to 42 avenue Foch.Footnote 54
On this basis, the Court found that ‘Equatorial Guinea has a plausible right to ensure that the premises which it claims are used for the purposes of its mission are accorded the protections required by Article 22 [VCDR]’.Footnote 55 The Court did not limit itself to establishing whether Equatorial Guinea plausibly held the rights it asserted under international law, but also whether, on the facts, Equatorial Guinea's claim that France had breached its asserted rights was plausible.Footnote 56 To make this finding, the Court considered whether Equatorial Guinea plausibly used the building at 42 avenue Foch for diplomatic purposes.
In the 2017 order in Ukraine v. Russian Federation, the Court followed the approach in Immunities and Criminal Proceedings. Ukraine's asserted rights arose both under the 1999 International Convention for the Suppression of the Financing of Terrorism (ICSFT),Footnote 57 and under the 1966 International Convention on the Elimination of All Forms of Racial Discrimination (CERD).Footnote 58 In relation to its asserted right under Article 18 ICSFT, Ukraine stated that ‘[t]he Russian Federation is violating that right, both by allowing its territory to serve as a launching pad for terrorist financing, and by engaging in that activity itself’.Footnote 59 The Court found that ‘Article 18 should be read together with Article 2 . . . because under Article 18 States parties must co-operate in the prevention of the offences set forth in Article 2’.Footnote 60 Therefore, the Court examined whether the acts alleged by Ukraine could plausibly be offences under Article 2 ICSFT, which amounted to enquiring into whether Ukraine's asserted right under Article 18 had been plausibly breached, as Ukraine had contended. The Court found that ‘Ukraine has not put before the Court evidence which affords a sufficient basis to find it plausible that [the elements under Article 2 ICSFT] are present’.Footnote 61
In relation to its asserted rights under Articles 2 and 5 CERD, Ukraine stated that ‘independent observers have documented the Russian Federation's infringements upon [such] rights’.Footnote 62 The Court stated that ‘a State party to CERD may avail itself of the rights under Articles 2 and 5 only if it is plausible that the acts complained of constitute acts of racial discrimination under the Convention’.Footnote 63 This statement showed that the Court focused on the Russian Federation's alleged breach of Articles 2 and 5, as argued by Ukraine. The Court then found that ‘on the basis of the evidence presented . . . by the Parties, it appears that some of the acts complained of by Ukraine fulfil this condition of plausibility’.Footnote 64 With respect to both the ICSFT and CERD, the Court followed Ukraine's line of argument, focusing on whether the acts allegedly carried out by the Russian Federation plausibly violated Ukraine's asserted rights.
The 2017 order in the Jadhav Case followed suit. India filed an application with the Court arguing that Pakistan had violated India's rights arising under Article 36(1) of the 1963 Vienna Convention on Consular Relations (VCCR).Footnote 65 According to India, Pakistan detained, tried and sentenced to death Kulbhushan Sudhir Jadhav, an Indian national, in breach of Article 36 VCCR. Pakistan did not dispute such factual allegations, but rather disputed that its conduct breached the VCCR. First, the Court found that ‘[t]he rights to consular notification and access between a State and its nationals . . . are recognized in Article 36, paragraph 1, of the [VCCR]’.Footnote 66 Second, the Court stated that Pakistan did not challenge India's assertion that Mr. Jadhav had been detained, tried and sentenced to death.Footnote 67 As a consequence, ‘taking into account the legal arguments and evidence presented, it appears that the rights invoked by India in the present case on the basis of Article 36, paragraph 1, of the [VCCR] are plausible’.Footnote 68 In the Jadhav Case, the Court followed the approach developed since Immunities and Criminal Proceedings, reviewing the available evidence relating to whether the conduct of the respondent state could plausibly breach the rights asserted by the applicant state.
The ICJ's orders on provisional measures suggest that the Court originally adopted a low plausibility standard, which only required it to assess whether the rights asserted by applicant states might exist in international law. In Immunities and Criminal Proceedings, the Court developed this low standard into a higher one, which requires it to assess whether the claim that the respondent state's conduct breached the applicant state's asserted rights is plausible.
3. Implications of plausibility as developed in the Court's jurisprudence
The adoption of the higher plausibility standard developed by the Court has far-reaching implications, which are discussed below.
3.1. The distinction between legal plausibility and factual plausibility
In his separate opinion appended to the 2011 order in Certain Activities, Judge Koroma stated that, owing to the vagueness of the test as adopted in Belgium v. Senegal, he was unsure as to ‘whether the Court requires an applicant seeking provisional measures to demonstrate the plausibility of its legal rights, the plausibility of its factual claims, or both’.Footnote 69 Judge Cançado Trindade also mentioned the distinction between legal and factual plausibility in his separate opinion in Ukraine v. Russian Federation. According to him:
the ICJ uses the term “plausible” not only in respect of rights . . . but also more widely in respect of the application of international instruments . . . thus disclosing two distinct forms of legal “plausibility”. Likewise, in the present Order, the ICJ uses the term “plausible” also in relation to facts . . . thus referring to another distinct form, this time of factual “plausibility”.Footnote 70
Judge Cançado Trindade distinguished two kinds of legal plausibility, ‘in respect of rights’ and ‘in respect of the application of international instruments’. However, the latter seems to correspond to prima facie jurisdiction. In assessing both plausibility ‘in respect of the application of international instruments’, and prima facie jurisdiction ratione materiae, the Court enquires into whether the conduct of the respondent state is capable of falling within the scope of the treaty invoked by the applicant state.Footnote 71 Judge Greenwood's declaration in the 2011 order in Certain Activities seems also to suggest a distinction between a legal and a factual component of plausibility, the former focused on rights and the latter on claims. According to Judge Greenwood, an applicant state ‘must show that there is at least a reasonable possibility that the right which it claims exists as a matter of law and will be adjudged to apply to that party's case’.Footnote 72
The mere legal assessment of plausibility would entail that the Court only needs to satisfy itself that, in the abstract, the applicant state might hold the rights it asserts on the merits. The Court thus assesses plausibility in respect of rights.Footnote 73 The factual assessment of plausibility would also require the Court to satisfy itself that the evidence submitted at the provisional measures stage shows that the conduct of the respondent state might breach the applicant states’ asserted rights. The Court thus assesses plausibility both in respect of rights, and in respect of claims.Footnote 74 While the focus of legal plausibility is the rights asserted by applicant states, the focus of factual plausibility is the conduct of respondent states as alleged by applicant states. In principle, the Court's enquiry into factual plausibility implies that the Court has satisfied itself of legal plausibility.
Legal plausibility could be sub-divided into two components. Assessing that, in abstracto, an applicant state has a right under international law requires the Court to establish both that the right concerned might have a legal basis, and that the state might hold such a right. A right's legal basis could be a treaty in force, in which case determining that an applicant state might hold that right would relate to whether that state is a party to the treaty in force under which the right concerned arises.Footnote 75 A right's legal basis could otherwise be a customary rule of international law, in which case ascertaining that an applicant state might hold that right would be contingent on whether that customary rule of international law is binding on that state.Footnote 76 However, since determining whether an applicant state might hold a right under international law necessarily entails a previous determination that such a right might exist in abstracto, both components should be subsumed under the single heading of legal plausibility.
Factual plausibility could also be sub-divided into two components. Finding that an applicant state's rights might have been breached by the respondent state requires the Court to assess both whether the respondent state's conduct is of such a kind that it might violate the applicant state's rights, and whether the evidence submitted by the applicant state sufficiently proves that the rights it asserts might have been breached.Footnote 77 Although the former assessment could seem to be purely legal, it is inseparable from the circumstances of a specific case. That assessment builds upon the purely legal finding of prima facie jurisdiction that the conduct of the respondent state falls within the scope of the legal instrument concerned,Footnote 78 as indicated by the fact that in all orders on provisional measures since Belgium v. Senegal the Court examined plausibility after having found that it had prima facie jurisdiction. The two components of factual plausibility can also be reduced to one. A finding that an applicant state's asserted rights might have been breached necessarily entails that the Court has already satisfied itself that the respondent state's conduct is of such a kind that it might violate such asserted rights.
Judge Abraham could be seen to have distinguished between legal and factual plausibility, although he did not make this distinction explicit. Under his non-exacting test, the Court should satisfy itself both that the rights asserted by the applicant state are ‘not patently non-existent’ under international law, and that it is ‘not manifestly to be ruled out’ that the respondent state's conduct might constitute a breach of such rights.Footnote 79 Under his higher test, the Court should first ‘establish a particular degree of probability that [the applicant state] holds the right claimed’, and second that there is ‘a particular degree of probability that the right is likely to be infringed through the other party's conduct’.Footnote 80 Although Judge Abraham did not explicitly refer to plausibility as requiring determinations of fact, the second element of both tests he formulated could presumably be satisfied only by applicant states submitting evidence corroborating their allegations that the rights they assert might have been breached. Judge Abraham's two stages of plausibility would correspond to Judge Koroma's distinction between legal plausibility and factual plausibility. Plausibility could be seen to have been originally conceived as combining two consecutive tests, one legal and one factual. Immediately after having seemingly conveyed his understanding of plausibility as a test requiring both legal and factual assessments, Judge Greenwood stated that he ‘agree[d] with the views expressed on this subject by Judge Abraham in his separate opinion in Pulp Mills on the River Uruguay’.Footnote 81 Already in 2011, Judge Greenwood might have read Judge Abraham's separate opinion to formulate plausibility as a two-stage test.
However, the Court has never explicitly assessed plausibility in two stages,Footnote 82 presumably because respondent states have so far challenged either the existence of the asserted rights under international law, or the allegation that their conduct breached the applicant states’ asserted rights. Nevertheless, since Immunities and Criminal Proceedings the Court seemed to apply a higher plausibility standard, which includes a factual assessment of the applicant state's claim. However, the adoption of this higher plausibility standard could be problematic. This higher standard could be inconsistent with the raison d’être of plausibility, which Judge Abraham identified as being limited to preventing the indication by the Court of binding provisional measures lacking the existence both of a plausible right held by the applicant state under international law, and, correspondingly, of a plausible obligation incumbent upon the respondent state.Footnote 83
3.2. Plausibility and the character of the applicant state's asserted rights
The distinction between legal plausibility and factual plausibility is useful to understand how the plausibility test operates in practice. Depending on whether the applicant state's asserted rights arise under customary international law or under a treaty, the parties before the Court are likely to focus their arguments either on both components of the plausibility test, or solely on factual plausibility.
Plausibility as adopted in Belgium v. Senegal only entailed an enquiry into whether the rights asserted by the applicant state might exist under international law. The existence of a state's rights is certain if such rights are codified by a treaty in force both for the applicant state and for the respondent state. Accordingly, plausibility as adopted in Belgium v. Senegal would only serve a function if an applicant state's rights arose under customary international law. Applicant states claimed to hold rights arising under customary international law in Certain Activities,Footnote 84 Construction of a Road Footnote 85 and Certain Documents and Data.Footnote 86 Since in these three cases it could in theory have been unclear whether the rights asserted by Costa Rica, Nicaragua and Timor-Leste existed under international law, the Court assessed the legal plausibility of such rights irrespective of whether the parties disputed their existence. Neither Nicaragua in Certain Activities, nor Costa Rica in Construction of a Road, disputed the existence of the right asserted by the state requesting provisional measures. Nonetheless, in both cases the Court endeavoured to find a legal basis on which the customary international law right to be free from environmental harm asserted by Costa Rica and Nicaragua could be plausibly founded.Footnote 87
However, in Certain Documents and Data Australia disputed that Timor-Leste's asserted rights to confidential communication with its legal counsel existed under international law.Footnote 88 In its analysis on legal plausibility, the Court found that Timor-Leste's:
right to communicate with its counsel and lawyers in a confidential manner with regard to issues forming the subject-matter of pending arbitral proceedings and future negotiations between the Parties . . . might be derived from the principle of the sovereign equality of States, which is one of the fundamental principles of the international legal order and is reflected in Article 2, paragraph 1, of the Charter of the United Nations.Footnote 89
Since Certain Documents and Data, the Court did not hear any request for provisional measures aimed at the preservation of rights arising solely under customary international law.
A plausibility test which includes establishing that the respondent state's conduct plausibly breached the applicant state's rights could prove useful also in cases in which the rights asserted on the merits arise under a treaty. However, in Belgium v. Senegal, Certain Activities and Construction of a Road, the Court's assessment focused only on whether the applicant states held the rights asserted under the treaty provisions invoked.
In Belgium v. Senegal, the Court found that Belgium's interpretation of the Torture Convention was ‘possible’, which satisfied the legal plausibility test.Footnote 90 In its 2011 order in Certain Activities, the Court was not entirely clear as to whether it assessed the legal plausibility or the factual plausibility of Costa Rica's asserted rights. The Court stated that ‘after a careful examination of the evidence and arguments presented by the Parties . . . the title to sovereignty claimed by Costa Rica over the entirety of Isla Portillos is plausible’.Footnote 91 The evidence and arguments presented by the parties in the oral proceedings suggest that, although both parties amply referred to the factual circumstances of the case,Footnote 92 such references were aimed at showing either that Costa Rica plausibly held rights of sovereignty over Isla Portillos, or that it did not. In Construction of a Road, the Court only observed that ‘under the 1858 Treaty of Limits between Costa Rica and Nicaragua, the latter enjoys “dominion and sovereign jurisdiction over the waters of the San Juan River” and that thus the river “belongs to Nicaragua”’.Footnote 93 In Certain Activities and in Construction of a Road, the Court made no explicit comments on factual plausibility, but was only concerned with finding a plausible legal basis for the right to sovereignty over Isla Portillos, which was asserted both by Costa Rica and by Nicaragua.
The Court's approach to the plausibility of treaty rights seemed to change in Immunities and Criminal Proceedings. However, both in that case, and in the Jadhav Case, the states concerned agreed on the factual basis of the applicant states’ requests for provisional measures, which might have obscured the Court's reasoning on plausibility. In Immunities and Criminal Proceedings, the Court addressed legal and factual plausibility in turn.Footnote 94 The Court's order contains virtually no discussion on whether Equatorial Guinea might hold the rights it asserted on the merits. Conversely, the Court underscored that both parties accepted that certain diplomatic services of the Embassy of Equatorial Guinea had been transferred to 42 Avenue Foch.Footnote 95 This suggests that the Court was chiefly concerned with issues of factual plausibility. Similarly, in the Jadhav Case the Court addressed legal and factual plausibility consecutively.Footnote 96 The Court only briefly observed that India plausibly held its asserted rights, instead focusing on factual plausibility. The Court emphasized the undisputed character of India's assertion that Mr. Jadhav had been detained, tried and sentenced to death,Footnote 97 and on that basis found that ‘the rights invoked by India in the present case on the basis of Article 36, paragraph 1, of the [VCCR] are plausible’.Footnote 98
Ukraine v. Russian Federation is the only instance in which the parties disagreed on the facts forming the basis of the applicant state's request for provisional measures. With respect to the ICSFT, the Court did not question whether the rights invoked by Ukraine under Article 18 ICSFT were legally plausible.Footnote 99 On the facts, the Court held that it was not plausible that the Russian Federation's conduct violated Ukraine's rights under Article 18 ICSFT, insofar as the acts allegedly committed by the Russian Federation did not plausibly fall within the definition of terrorism under Article 2 ICSFT. With respect to CERD, the Court did not question the legal plausibility of Ukraine's rights under CERD. It only explicitly dealt with factual plausibility.Footnote 100 Following the approach in Immunities and Criminal Proceedings, in Ukraine v. Russian Federation the Court chiefly examined the factual plausibility of Ukraine's asserted rights.
The Court's jurisprudence shows a change in the assessment of the plausibility of rights arising under a treaty. Until Construction of a Road the Court focused on whether it is plausible that applicant states hold their asserted rights, whereas since Immunities and Criminal Proceedings the Court has also assessed whether the conduct of the respondent state plausibly breaches the rights of the applicant state. The Court moved from a purely legal assessment of plausibility, to a plausibility test including assessments of facts.Footnote 101 The main difference between the cases before and after Immunities and Criminal Proceedings could be that in the latter respondent states clearly disputed the applicant states’ allegations of fact. This may be correct in relation to Immunities and Criminal Proceedings, in which the parties disputed the date on which Equatorial Guinea's diplomatic services were transferred to 42 Avenue Foch. While Equatorial Guinea argued that the transfer took place on 4 October 2011,Footnote 102 the date after which the French authorities allegedly carried out four searches on the premises of 42 Avenue Foch,Footnote 103 France contended that the transfer took place on 27 July 2012,Footnote 104 the date after which the French authorities allegedly carried out no attachment measure.Footnote 105 Similarly, in Ukraine v. Russian Federation, the Russian Federation disputed the facts as presented by Ukraine in relation to alleged violations of CERD.Footnote 106
However, in relation to the ICSFT, the Russian Federation did not challenge that certain events alleged by Ukraine had taken place, while challenging their characterization as acts of terrorism under the ICSFT.Footnote 107 Similarly, in the Jadhav Case the parties agreed on the facts alleged by India. Pakistan did not challenge that ‘one of [India's] nationals has been arrested, detained, tried and sentenced to death in Pakistan without having been notified by the same State or afforded access to him’.Footnote 108 Moreover, in Certain Activities Nicaragua disputed certain facts at the basis of Costa Rica's request for provisional measures. Nicaragua argued both that its police operations in the disputed area were part of routine activities,Footnote 109 and that its operations around the caño related to ‘débroussaillage et . . . nettoyage’ of an existing canal.Footnote 110 Admittedly, Nicaragua's aim in challenging Costa Rica's factual assertions was to show that Costa Rica did not plausibly hold the right to sovereignty over Isla Portillos under the 1858 Treaty of Limits. Nevertheless, since Nicaragua disputed the facts alleged by Costa Rica, nothing prevented the Court from analyzing both the legal plausibility of Costa Rica's asserted rights, and whether the factual allegations relating to the breach of Costa Rica's sovereignty over Isla Portillos were plausible. Both the Jadhav Case and Certain Activities suggest that a challenge by the respondent state of the facts alleged by the applicant state was not determinative of the Court's approach to plausibility adopted since Immunities and Criminal Proceedings. The reason which led the Court to adopt a plausibility standard requiring the appreciation of whether a respondent state's conduct plausibly breaches the applicant state's asserted rights remains unclear.
Since the development of the plausibility test in Immunities and Criminal Proceedings, states have requested the Court to indicate provisional measures only for the protection of treaty rights. However, the issue arises whether, if requested to indicate provisional measures for the preservation of rights arising under customary international law, the Court would examine the factual plausibility of an applicant state's asserted rights. In Certain Activities, Certain Documents and Data and Construction of a Road, facts were either undisputed, or disputed with the sole aim of showing that an applicant state's asserted rights were not legally plausible. However, it seems possible that the Court would assess the factual plausibility of customary international law rights, also because rights arising under a treaty could subsequently become part of customary international law, or that rights under customary international law could be later codified in a treaty.Footnote 111
By assessing the factual plausibility of an applicant state's rights, whether arising under a treaty or under customary international law, the Court would broaden the original raison d’être of plausibility, namely to prevent the imposition of binding provisional measures on a respondent state without reviewing that such a state plausibly owes an obligation to an applicant state. Factual plausibility entails a review, although limited, of the merits of an applicant state's claim. The aim of such a review could be to reject claims which, already at the provisional measures stage, appear to be manifestly unsupported by evidence. Factual plausibility thus increases the protection afforded to the respondent state at the provisional measures stage. In this perspective, the developments since Immunities and Criminal Proceedings appear to be mostly favourable to respondent states.
However, the risk could be that, by reviewing the factual basis of an applicant state's claim, the Court might be seen to prejudge its decision on the merits. Judge Owada expressed concerns about prejudging the merits in his separate opinion in Ukraine v. Russian Federation.Footnote 112 Nevertheless, assessing factual plausibility does not necessarily determine the prejudgment of the merits. Doubts comparable to those on prejudgment of the merits existed with respect the Court's assessment of prima facie jurisdiction.Footnote 113 In its 1951 order on provisional measures in Anglo-Iranian Oil Co., the Court found on jurisdiction that it was ‘empower[ed] . . . to entertain the Request for interim measures of protection’.Footnote 114 In its subsequent 1952 judgment, the Court held that it had ‘no jurisdiction to deal with the case submitted to it by the . . . United Kingdom’.Footnote 115 A decision on prima facie jurisdiction made at the provisional measures stage was not confirmed in the subsequent phases of the proceedings. Similarly, although one could conceive of plausibility as a higher standard than the one for prima facie jurisdiction,Footnote 116 it does not necessarily follow that, by assessing whether the applicant states’ rights are factually plausible, the Court would inevitably prejudge the merits. After finding at the provisional measures stage that the applicant state's asserted rights are factually plausible, in the later phases of the proceedings the Court could find either that such rights do not exist under international law, or that the respondent state's conduct did not breach them.
However, while the theoretical risk of prejudgment could be avoided, the practical risk which would remain is that of overburdening provisional measures proceedings with matters more appropriately examined at the merits.Footnote 117 States might also be tempted to submit copious amounts of evidence, which Practice Direction XI discourages.Footnote 118 The result could be a longer duration of provisional measures proceedings. However, in the three cases in which the Court assessed plausibility of claims in addition to plausibility of rights, the length of provisional measures proceedings was comparable to earlier cases. In Immunities and Criminal Proceedings, Equatorial Guinea filed its request on 29 September 2016 and the Court made its order two months and eight days later, on 7 December 2016. In Ukraine v. Russian Federation, the request was filed on 16 January 2017 and the order made three months and three days later, on 19 April 2017. Owing to the extreme urgency in the Jadhav Case, the Court made its order within ten days of receiving India's request on 8 May 2017. Such delays are in line with the Court's usual practice. For example, in Certain Documents and Data the Court made its order on 3 March 2014, two months and 14 days after Timor Leste's request of 17 December 2013. In Belgium v. Senegal it took three months and ten days for the order to be made, longer than it took in Ukraine v. Russian Federation. If assessing factual plausibility threatens to overburden provisional measures proceedings and thus increase their duration, this risk has yet to materialize.
3.3. Plausibility and prima facie jurisdiction
The Court's elaboration on plausibility and prima facie jurisdiction raises issues concerning the relationship between these two requirements for indicating provisional measures.
3.3.1. The overlap between plausibility and prima facie jurisdiction
The Court's assessment of factual plausibility could overlap with its assessment of prima facie jurisdiction, as a consequence of the recent jurisprudential developments concerning both of these requirements.Footnote 119
The Court has recently adopted the approach of consistently examining whether the acts alleged by the applicant state fall within the scope ratione materiae of the treaty whose jurisdictional clause is invoked.Footnote 120 Jurisdictional clauses in treaties generally provide for jurisdiction to settle disputes concerning their ‘interpretation or application’, which limits the jurisdiction ratione materiae of international courts and tribunals to the subject-matter regulated in the treaty concerned.Footnote 121 Therefore, at the provisional measures stage the issue could arise concerning whether the acts alleged by the applicant state prima facie fall within the scope ratione materiae of the relevant treaty, and thus whether the dispute is one concerning the interpretation and application of that treaty.
This development is exemplified by the Court's 2008 order in Georgia v. Russian Federation, a case submitted under Article 22 CERD.Footnote 122 Georgia argued that ‘as regards the Court's jurisdiction ratione materiae, the object and purpose of CERD is to eliminate racial discrimination in “all its forms and manifestations”’,Footnote 123 and, inter alia, that ‘ethnic Georgians have been “targeted, and forcibly expelled from [Abkhazia and South Ossetia] in great numbers and denied the right to return over the course of more than a decade”’.Footnote 124 The Russian Federation contended that:
the dispute . . . before this Court is not a dispute on racial discrimination under [CERD], but rather a dispute relating to the use of force, the principles of territorial integrity and self-determination, non-interference in the internal affairs of States, armed activities and international humanitarian law.Footnote 125
The Russian Federation concluded ‘that “the Court manifestly lacks jurisdiction in the present case”’.Footnote 126 The Court found that ‘the acts alleged by Georgia appear to be capable of contravening rights provided for by CERD, even if certain of these alleged acts might also be covered by other rules of international law . . .’.Footnote 127 According to the Court:
this is sufficient at this stage to establish the existence of a dispute between the Parties capable of falling within the provisions of CERD, which is a necessary condition for the Court to have prima facie jurisdiction under Article 22 of CERD.Footnote 128
Since the introduction of the plausibility test in 2009, the Court has heard four cases in which the jurisdictional basis was a compromissory clause in a treaty. In Belgium v. Senegal, the scope of the Court's jurisdiction ratione materiae was undisputed. In Immunities and Criminal Proceedings, France did not raise the issue of the Court's jurisdiction ratione materiae under the VCDR.Footnote 129 Nevertheless, the Court held that:
[i]n order to determine whether it has jurisdiction – even prima facie – [it] must also ascertain whether such a dispute is one over which it might have jurisdiction ratione materiae on the basis of Article I of the Optional Protocol [to the VCDR].Footnote 130
The Court added that:
the rights apparently at issue may fall within the scope of Article 22 [VCDR], . . . and . . . the acts alleged by the Applicant in respect of the building on avenue Foch appear to be capable of contravening such rights. Indeed, the premises which, according to Equatorial Guinea, house its diplomatic mission in France were searched on several occasions and were attached (saisie pénale immobilière); they could also be subject to other measures of a similar nature.Footnote 131
However, in assessing the factual plausibility of Equatorial Guinea's rights the Court similarly noted that the building at 42 Avenue Foch ‘has been searched a number of times and has been attached (saisie pénale immobilière)’.Footnote 132 This appears to overlap with the Court's examination of prima facie jurisdiction ratione materiae, since in respect of both requirements the Court sought to establish whether France's alleged conduct might be a breach of Equatorial Guinea's rights under the VCDR.
In Ukraine v. Russian Federation, concerning the ICSFT the Court stated that it:
must ascertain whether the acts of which Ukraine complains are prima facie capable of falling within the provisions of the Convention . . . The Court considers that at least some of the allegations made by Ukraine . . . appear to be capable of falling within the scope of the ICSFT ratione materiae.Footnote 133
However, in its discussion on factual plausibility the Court stated that the rights invoked by Ukraine under the ICSFT could be plausible only if the acts alleged by Ukraine itself plausibly ‘constitute offences under Article 2 of the ICSFT’.Footnote 134 Article 2 limits the scope ratione materiae of the ICSFT by determining which acts fall within the definition of terrorism under that convention. The enquiry into factual plausibility seems to overlap with that into prima facie jurisdiction ratione materiae. In respect of both requirements, the Court analyzed whether the acts alleged by Ukraine could be acts of terrorism under the ICSFT.
In relation to CERD, the Court found that:
[t]he acts referred to by Ukraine, in particular the banning of the Mejlis and the alleged restrictions upon the cultural and educational rights of Crimean Tatars and ethnic Ukrainians, appear to be capable of falling within the scope of CERD ratione materiae.Footnote 135
When discussing factual plausibility, the Court stated that:
in the context of a request for the indication of provisional measures, a State party to CERD may avail itself of the rights under Articles 2 and 5 only if it is plausible that the acts complained of constitute acts of racial discrimination under the Convention.Footnote 136
However, this seems hardly to differ from establishing whether banning the Mejlis and restricting the cultural and educational rights of Crimean Tatars and ethnic Ukrainians fall within the scope ratione materiae of CERD. In respect of both prima facie jurisdiction and factual plausibility, the Court conducted an enquiry into the character of the rights asserted by Ukraine as acts of racial discrimination under CERD.
In the Jadhav Case the Court confirmed that:
[i]n order to determine whether it has jurisdiction – even prima facie jurisdiction – the Court must also ascertain whether such a dispute is one over which it might have jurisdiction ratione materiae on the basis of Article I of the Optional Protocol [to the VCCR].Footnote 137
Since Pakistan's alleged conduct concerned the arrest, detention and sentencing to death of an Indian national, the Court found that:
the alleged failure by Pakistan to provide the requisite consular notifications with regard to the arrest and detention of Mr. Jadhav, as well as the alleged failure to allow communication and provide access to him, appear to be capable of falling within the scope of the Vienna Convention ratione materiae.Footnote 138
With regard to factual plausibility, the Court recalled India's submissions that ‘one of its nationals has been arrested, detained, tried and sentenced to death in Pakistan without having been notified by the same State or afforded access to him’,Footnote 139 and that ‘Mr. Jadhav has not been informed without delay of his rights with regard to consular assistance or allowed to exercise them’.Footnote 140 Consequently, ‘taking into account the legal arguments and evidence presented, it appears that the rights invoked by India in the present case on the basis of Article 36, paragraph 1, of the [VCCR] are plausible’.Footnote 141 The Court seems to have considered the character of the acts alleged by India both under the heading of prima facie jurisdiction, and under the heading of factual plausibility.
Plausibility and prima facie jurisdiction have distinct functions in provisional measures proceedings before the Court. While the former aims to prevent the imposition on a respondent state of obligations binding under Article 41 of the Court's Statute which lack a plausible legal basis under international law, the latter is intended to preserve the consensual character of the Court's jurisdiction. Although it examines the same set of facts, in establishing whether these two requirements are met the Court focuses on different legal aspects of a request for provisional measures. Furthermore, the character of the Court's assessment seems to be different for the two requirements. Prima facie jurisdiction ratione materiae is a purely legal assessment of whether the alleged conduct of a respondent state might, in the abstract, fall within the scope of a treaty invoked by an applicant state. By contrast, factual plausibility requires the Court to assess the evidence submitted before it in order to determine whether the respondent state might have breached the applicant state's asserted rights.
3.3.2. The standards of plausibility and prima facie jurisdiction
It is also conceivable that the standard for prima facie jurisdiction is not the same as the one for plausibility.Footnote 142 The comments of certain judges in their individual opinions could be instructive in this regard. However, judges do not appear unanimous in their views. For example, Judge Koroma wrote that:
[b]oth the new [plausibility] standard and the prima facie jurisdiction standard would require a party to demonstrate that it has a reasonable chance of eventually obtaining a judgment on the merits in its favour before it could obtain provisional measures.Footnote 143
Judge Greenwood wrote on prima facie jurisdiction that the ‘threshold which the applicant has to cross is . . . set quite low’,Footnote 144 while on plausibility he suggested that the applicant state ‘must show that there is at least a reasonable possibility that the right which it claims exists as a matter of law and will be adjudged to apply to that party's case’.Footnote 145
Judge Owada made some significant remarks in his separate opinion in Ukraine v. Russian Federation. According to him, ‘the Court's choice of the word “plausible” reveals that the Court at the very least wished to distinguish it from the “prima facie” standard that applies for jurisdiction’.Footnote 146 Moreover, he wrote that ‘the Court's jurisprudence on [plausibility] reveals that the standard applied has always been fairly low’.Footnote 147 Besides stating that ‘plausible’ and ‘prima facie’ are distinct thresholds, Judge Owada did not explain which one he conceived as being higher. However, he stated that in the 2011 order in Certain Activities the Court ‘suggested that the degree of certainty required to find a right plausible could be . . . lower than fifty per cent in the context of the asserted rights of the opposing party’.Footnote 148 Judge Owada based his view on the Court's statement that:
after a careful examination of the evidence and arguments presented by the Parties . . . the title to sovereignty claimed by Costa Rica over the entirety of Isla Portillos is plausible; [and] the Court is not called upon to rule on the plausibility of the title to sovereignty over the disputed territory advanced by Nicaragua.Footnote 149
According to him, ‘[i]f “plausibility” were to imply a degree of certainty greater than fifty per cent, then a finding that [the applicant state's] claim was plausible would necessarily imply that [the respondent state's] claim was not plausible’.Footnote 150
Judge Owada's comments suggest that, at least in certain judges’ minds, ‘plausible’ and ‘prima facie’ entail distinct standards. While they are both generally conceived as being low standards, it is possible that ‘plausible’ is a higher standard than ‘prima facie’. Since its formulation in 1957,Footnote 151 the Court found that it lacked prima facie jurisdiction only on three occasions: the Legality of Use of Force cases,Footnote 152 DRC v. Rwanda Footnote 153 and Immunities and Criminal Proceedings.Footnote 154 By contrast, since 2009 the Court already rejected a request for provisional measures because the rights asserted by the applicant state were not plausible.Footnote 155 Although this does not necessarily mean that the plausibility threshold is higher than the one for prima facie jurisdiction, it might be considered to be an indication in this sense.
Judge Owada's comments seem only to apply to cases in which the respondent state asserts that it holds the same rights as the applicant state, such as in Certain Activities. Stating that a threshold lower than 50 per cent could satisfy the plausibility test does not dispel all doubts on the plausibility standard. Nevertheless, it conveys that, at least in the cases to which Judge Owada referred, that standard could be higher than the one for prima facie jurisdiction. The views expressed by Judge Owada seem to recognize the evolution in the Court's provisional measures jurisprudence towards a higher plausibility standard,Footnote 156 and could also explain the terminological difference, adopted by the Court, between ‘plausible’ and ‘prima facie’.
Another difference in the standards for plausibility and prima facie jurisdiction relates to the possibility that plausibility be assessed with respect to both the rights asserted by the applicant state, and the rights asserted by the respondent state. In Ukraine v. Russian Federation, Judge ad hoc Pocar suggested that assessing the plausibility of the applicant state's rights would automatically entail that ‘due regard [is given] to the rights of the respondent’.Footnote 157 Judge Greenwood expressed a different view. In his dissenting opinion in Certain Documents and Data, he stated that ‘requiring that the seized material be sealed until the final judgment of the Court . . . deprives Australia of any opportunity . . . to have its intelligence officers inspect the material’.Footnote 158 According to him, ‘the right of Australia to exercise its criminal jurisdiction and its right to protect the safety of its officials must also be regarded as plausible’.Footnote 159 Judge Greenwood's view finds support in the remarks of Judge ad hoc Thierry in Arbitral Award of 31 July 1989.Footnote 160
However, this view does not seem to be supported by Article 41 of the Court's Statute, under which provisional measures may be indicated to ‘preserve the respective rights of either party’. Differently from Article 41, Article 290 UNCLOS states that provisional measures may be prescribed ‘to preserve the respective rights of the parties’, which suggests that provisional measures prescribed by an international court or tribunal having jurisdiction under Part XV UNCLOS are aimed at preserving the rights of both parties.Footnote 161 Judge Greenwood made his remarks on plausibility in the context of a discussion on whether an undertaking by the Attorney-General of Australia removed the risk of irreparable prejudice to Timor-Leste's asserted rights. Such remarks could be seen to be case-specific, and thus only to apply in cases similar to Certain Documents and Data.
The wording of Article 41 is nonetheless sufficiently vague to allow the Court to indicate provisional measures for the preservation of the rights of both parties. Considerations of even-handedness could also suggest that provisional measures ought to preserve the rights of both parties. Such an approach could apply at least in cases in which both parties assert rights on the merits, such as Certain Activities in which both Costa Rica and Nicaragua asserted sovereignty over Isla Portillos. In similar cases, nothing seems to preclude the assessment of plausibility in respect of the rights of both the applicant state and the respondent state. Whichever view one takes, the possible assessment of plausibility of the rights of a respondent state would mark a difference with respect to the standard for assessing prima facie jurisdiction.
3.4. Plausibility and provisional measures in interpretation proceedings
In interpretation proceedings, plausibility as a requirement for indicating provisional measures seems to be distinct from plausibility as a requirement for indicating provisional measures in ordinary contentious proceedings. Since Belgium v. Senegal, the Court has heard one interpretation case in which provisional measures were requested.
In Temple of Preah Vihear (Interpretation), Cambodia requested the Court to interpret its 1962 Temple of Preah Vihear judgment.Footnote 162 In the order of 18 July 2011, the Court stated, in relation to the rights that Cambodia asserted on the merits, that:
at this stage in the proceedings, [it] does not have to rule definitively on the interpretation put forward by Cambodia of the 1962 Judgment and on the rights it claims to derive therefrom; and . . . for the purposes of considering the request for the indication of provisional measures, [it] need only determine whether those rights are at least plausible.Footnote 163
Since Cambodia's request for provisional measures arose in the context of interpretation proceedings,Footnote 164 the Court found that the rights Cambodia asserted on the merits were those, recognized in the 1962 judgment, of sovereignty over the area around the Temple of Preah Vihear, and to seek and obtain the withdrawal of Thailand's military forces from that area.
Concerning the plausibility of Cambodia's rights, the Court stated that:
the interpretation of the 1962 Judgment put forward by Cambodia in order to assert its rights – namely, the right to respect for its sovereignty in the area of the Temple of Preah Vihear and its right to territorial integrity – is that the Court was only able to reach these conclusions once it had recognized the existence of a frontier between the two States and found that the Temple and its “vicinity” were on the Cambodian side of that frontier.Footnote 165
On this basis, the Court concluded that ‘the rights claimed by Cambodia, in so far as they are based on the 1962 Judgment as interpreted by Cambodia, are plausible’.Footnote 166 The Court's enquiry into plausibility appears primarily to relate to its legal component, since it concerned the existence, alleged by Cambodia, of its rights to sovereignty and territorial integrity, as recognized in the 1962 judgment.
The Court did not conduct any enquiry into factual plausibility, which would seem consistent with the approach to plausibility adopted before Immunities and Criminal Proceedings. Nevertheless, this approach by the Court also appears justified by the fact that Cambodia's request for provisional measures arose in the context of interpretation proceedings. The Court's jurisprudence suggests that in interpretation cases the Court itself cannot consider the present-day conduct of the states before it. In the 1950 judgment in Asylum (Interpretation), the Court held that the object of interpretation proceedings is ‘solely to obtain clarification of the meaning and the scope of what the Court has decided with binding force, and not to obtain an answer to questions not so decided’,Footnote 167 and that ‘[t]he “gaps” which the Colombian Government claims to have discovered in the Court's Judgment in reality are new questions, which cannot be decided by means of interpretation’.Footnote 168 The Court confirmed this view in later cases.Footnote 169 It emerges from the Court's jurisprudence that, by submitting a request for interpretation, a state cannot ask the Court to consider questions that have not already been decided in the judgment of which interpretation is sought. This limit would prevent the Court from considering legal issues stemming from the alleged conduct of a respondent state subsequent to the judgment of which interpretation is sought.
The same limit would seem also to apply to requests for provisional measures filed in interpretation proceedings. There is no apparent reason why the Court should be able to consider present-day conduct in the context of provisional measures, while at the same time not being able to do so when considering the merits of an interpretation case. As a consequence of this approach, plausibility in interpretation proceedings should be understood as being distinct from plausibility in ordinary contentious cases. Since in interpretation proceedings the Court is not called upon to consider the conduct of a state subsequent to the judgment of which interpretation is sought, assessing factual plausibility seems unfeasible. It would follow that in interpretation proceedings plausibility is a purely legal test, lacking the factual component which the Court would assess in ordinary contentious cases.
This conclusion could seem to be artificial when assessed against the background of Temple of Preah Vihear (Interpretation). Thailand suggested that by filing a request for interpretation, Cambodia was requesting the Court to address issues of compliance with the 1962 judgment.Footnote 170 Cambodia rejected such allegations.Footnote 171 Regardless of the merits of Thailand's arguments, filing a request for interpretation in order to ensure compliance with an earlier judgment would seem to establish a connection between the request itself and the conduct of a state subsequent to the judgment of which interpretation is sought. Even if interpretation proceedings were filed as a means to react to non-compliance with an earlier judgment, the Court's function would nonetheless be limited to interpreting the earlier judgment. The reasons for filing a request for interpretation remains distinct from the scope of the Court's jurisdiction under Article 60 of the Statute.
4. Key principles concerning plausibility
It emerges from the cases since Belgium v. Senegal that the Court has consistently assessed whether the rights of applicant states were legally plausible. Although the Court has not yet assessed the factual plausibility of rights arising only under customary international law, it might do so in future cases. Based on its jurisprudence up to the Jadhav Case, the Court could formulate plausibility as a test in two consecutive stages: first, the assessment of whether an applicant state plausibly holds the rights it asserts; second, the assessment of whether a respondent state's alleged conduct plausibly breaches the applicant state's asserted rights. This formulation could also guide states involved in provisional measures proceedings in presenting their submissions before the Court.
By way of conclusion, it seems possible to articulate some key principles concerning the current formulation of the plausibility test as a requirement for indicating provisional measures under Article 41 of the ICJ's Statute:
1. The raison d’être of plausibility is to protect respondent states against requests for provisional measures either lacking a plausible legal basis under international law, or not based on a plausible claim on the merits;
2. The concept of plausibility could be divided into two components: (i) legal plausibility, which aims to establish whether the rights asserted by the applicant state might have a legal basis under international law, and thus focuses on plausibility of rights; and (ii) factual plausibility, which aims to establish whether the conduct of the respondent state might breach the rights plausibly asserted by the applicant state, and thus focuses on plausibility of claims;
3. In order to assess factual plausibility, the Court should previously satisfy itself that the rights asserted by the applicant state are legally plausible;
4. Assessing factual plausibility entails some review of the evidence submitted by the parties at the provisional measures stage and concerning the alleged breach of the applicant state's asserted rights by the respondent state. Such a review is necessarily limited owing to the urgent character of provisional measures proceedings, and in no way prejudges the merits of the case;
5. The assessment of factual plausibility could appear to overlap with the assessment of prima facie jurisdiction ratione materiae. However, these requirements have distinct functions in the context of a request for provisional measures, and the standard for assessing plausibility is conceivably higher than the standard for assessing prima facie jurisdiction;
6. In provisional measures incidental to ordinary contentious proceedings, the Court assesses legal plausibility and factual plausibility consecutively;
7. If in ordinary contentious proceedings the rights asserted by the applicant state arise under customary international law, legal plausibility could be crucial depending on whether the existence of such rights is disputed between the parties. Factual plausibility could equally be crucial if the respondent state disputes either the applicant state's factual allegations, or the characterization of the alleged facts;
8. If in ordinary contentious proceedings the rights asserted by the applicant state arise under a treaty, legal plausibility in principle raises no issue so long as the treaty concerned is in force between the parties. Factual plausibility would be the focus of the plausibility test, provided that the respondent state disputes either the applicant state's factual allegations, or the characterization of the alleged facts; and
9. In provisional measures incidental to interpretation proceedings, plausibility should only entail an assessment of whether the applicant state's rights stemming from the judgment of which interpretation is sought have a plausible legal basis.
