The End of the Affair: the Extinction of Disputes in International Law

Determining the existence of a dispute is key to establishing and exercising jurisdiction in international adjudication by international courts and tribunals. Much has been written on the definition and emergence of a dispute, but there has been almost no scholarly consideration of the question of the ending of a dispute. This article contends that the extinction of a dispute is a separate and independent legal process, distinct from the mere non-fulfilment of the criteria for the definition of a dispute. It conducts a thorough study of the different means of extinguishing a dispute as recognised thus far in the case law of the ICJ and ITLOS, identifying and analysing three methods by which a dispute may be extinguished. It then demonstrates that each such method is deeply rooted in core legal principles related to the international judicial function.


Introduction
Disputes are central to international law and international adjudication.The primary purpose of international adjudication is the pacific settlement of disputes.1The existence (or otherwise) of a dispute can have important consequences, particularly for the exercise of jurisdiction by international courts and tribunals.2As such, identifying the existence of a dispute is a fundamental aspect of international adjudication.Much has been written on the definition and emergence of a dispute.3However, there has been little-to-no scholarly consideration of the question of the ending of a dispute.4This is not to say that the question of the extinction of a dispute has not yet been at issue before an international court -far from it.In 2021, the International Tribunal for the Law of the Sea (ITLOS) was required to rule on whether a dispute between one party (Mauritius) and a third party (the United Kingdom, UK) had been effectively resolved and thus extinguished.5 Its surprising conclusion that the dispute in question was indeed extinguished -by a non-binding advisory opinion no less -is discussed in detail below.6 Similarly controversial, the International Court of Justice (ICJ) has ruled on more than one occasion, most recently in the Silala case of 2022, that a dispute between parties had been wholly or partly extinguished because the object of the claim had "disappeared".7 These examples, amongst others,8 demonstrate that the question of the extinction of a dispute is highly relevant and that the answer to this question remains unclear.This is no mere theoretical or abstract issue, but one that has real and concrete import for international adjudication.When and how, exactly, is a dispute "settled", and what does it mean for a dispute to be extinguished?Is this merely the other side of the coin of the definition of a dispute; in other words, does a dispute simply emerge and disappear in accordance with whether or not the definitional criteria of a dispute are met?Or is it a distinct legal process by which a dispute is ended definitively?How can we identify the end of an affair, and can it truly be ended?These questions specifically and this area (the extinction of disputes) more generally remain unclarified and underexplored in international law.
This article seeks to establish that the extinction of a dispute is a separate and independent legal process, distinct from the question of the fulfilment or non-fulfilment of the criteria for the definition of a dispute.It is contended that this process of extinction has specific legal consequences which directly impact the exercise of international adjudicative jurisdiction.It is further contended that these consequences ultimately stem from principles related to the delimitation of the international judicial function and its role within the international legal order, most notably the international rule of law and the principle of legal certainty.In making and substantiating this claim, this article presents an essential contribution to and clarification of the legal framework for the extinction or disappearance of a dispute in international law.
The focus of the article is on inter-state disputes, and particularly on the treatment of the dispute concept by the ICJ and by ITLOS, and is based on a thorough survey of the case law of these bodies.Perhaps more than any other such bodies in international adjudication, both the Court and Tribunal are strongly concerned with the definition of a dispute, not least because the existence of a dispute is written into their formal procedural rules as a prerequisite Thin LAPE 23 (2024)  for the exercise of jurisdiction.9Both bodies therefore share equivalent procedural restrictions.In addition, there is a relatively high degree of inter-regime interaction between them when it comes to the concept of a dispute,10 and as such it is logical to consider them both together.
The first part of the article (Section 2) begins with an overview of the concept of a dispute in international law.It examines in turn: why and when the existence of a dispute is of legal relevance in Court or Tribunal procedure; how a dispute has been defined thus far; and the concept of the extinction of a dispute.Here it sets out the key considerations with regard to the relationship between the definition of a dispute and its extinction.In so doing, it establishes the premises and sets the groundwork for the ensuing argument, namely that the extinction of a dispute is a separate legal process with distinct legal effects.Section 3 conducts a comprehensive analysis of the different means by which disputes may be said to have been extinguished in the jurisprudence of the ICJ and ITLOS.Three categories of such methods are identified on the basis of the case law of ITLOS and the ICJ: mutual consent of the parties (via both binding and non-binding modes of settlement); authoritative resolution by a third party (including the effect of res judicata and the authoritative interpretation of the parties' claims); and the situation where a dispute becomes "without object" or "moot".The focus of this analysis is to establish to what extent each such method of extinction operates as a distinct legal process beyond the mere application of definitional criteria.Finally, Section 4 draws together the preceding analysis and, drawing from a more systemic perspective, situates the role of the extinction of a dispute in connection with the international judicial function and related legal principles including the international rule of law.

2
The Emergence and Extinction of Disputes in International Law

The Relevance of the Existence of a Dispute
The relevance of the concept and definition of a dispute is most visible at the stage of admissibility, i.e. regarding the determination of whether or not the Court's or Tribunal's jurisdiction is to be exercised.11There are two ways in which the existence or otherwise of a dispute may be seen to have legal effect in this regard, namely (a) as a prerequisite for the exercise of jurisdiction, and (b) as a bar to the exercise of jurisdiction by way of application of the Monetary Gold rule.
First, the existence of a dispute between the parties to the case is a prerequisite for the exercise of jurisdiction of both the ICJ and ITLOS.12This is logical: there would be little point in adjudication if the parties were in full agreement over the issues at hand.In the Northern Cameroons case, the Court noted that the existence of a dispute was a vital element of the distinction between its advisory and contentious functions.13The purpose behind this requirement is, accordingly, to preserve the contentious nature of the case and the Court's "judicial function".14Temporally speaking, the dispute must exist between the parties at the point at which the application is made to the Court or Tribunal.15Thus, if the dispute only arises after the application is made, then the requirement is not fulfilled and the case will not be admissible.16By extension, and as will be argued in more detail below, if the dispute is extinguished prior to the initiation of proceedings, the application will similarly be inadmissible.17 The second main situation in which the existence of a dispute may be legally relevant relates to the application of the so-called "Monetary Gold"  rule.18In essence, the existence of a dispute between one of the parties to the case at hand and a third party may prevent the exercise of jurisdiction.This will be so if, by addressing the claims in the case at hand, the Court or Tribunal would be required to decide on matters that fall within the dispute with the third party.19This is also known as the indispensable third party rule.20 As was stated in the Monetary Gold case, the ICJ cannot exercise its jurisdiction over a case in which a non-consenting state's "legal interests would … form the subject-matter of the decision".21This is the situation that ITLOS was required to address in Mauritius v. Maldives.22 In that case, Mauritius had requested the Tribunal to rule on certain issues of maritime delimitation between itself and the Maldives.23The Maldives objected that there was an ongoing territorial dispute between Mauritius and the UK over the Chagos Archipelago which fell within the disputed area, and that the UK was therefore an indispensable third party in the case.24 The Tribunal held that it was therefore required to decide whether the dispute between Mauritius and the UK "has been resolved in favour of Mauritius, [in which case] the United Kingdom may not be regarded as an indispensable party and the Monetary Gold principle would not apply."25 The existence of a dispute between one party and a third party, and the question of whether the Court or Tribunal would be required to rule on the legal interests of that third party are not necessarily the same thing.26Not every dispute with a third party will incur the indispensable third party rule; similarly, not every application of the third party rule will involve an ongoing dispute as such.There may even be situations in which a dispute between one party and a third party is resolved and extinguished, but there remains a legal interest in the subject matter of the decision on the part of the third party which would still prevent the exercise of jurisdiction in accordance with the Monetary Gold rule.Nonetheless, the Mauritius v. Maldives case demonstrates that there is potential for overlap between the "legal interests" of the indispensable third party and the existence of a dispute between that third party and a party to the case.27Thus, the existence of a dispute will be of legal relevance to the exercise of jurisdiction in such cases.
Beyond these two scenarios, there are other circumstances in which a dispute may be relevant.For example, the obligation under Article 283 UNCLOS to exchange views28 does not apply when there is disagreement over the existence of a dispute in the first place.29Other treaty-based rules may add further situations in which the determination of the existence of a dispute is necessary.Having now established the scenarios in which the existence of a dispute may be seen to have legal relevance, particularly with regard to the exercise of jurisdiction, the following section delves into the definition of a dispute and when it may be said to have arisen.

Definition of a Dispute
In situations where it is necessary to determine the existence of a dispute (as discussed above), the Court or Tribunal applies the established definition of such.In reality, more often than not the issue is not so much whether a dispute exists at all, but rather the scope of the dispute, or which aspects of the applicant's claims were the subject of a dispute at the point of application.30In either case, the definition of a dispute is applied.
The ICJ has defined the term "dispute" variably over the years as "a disagreement on a point of law or fact, a conflict of legal views or of interests between two persons"31 and "a situation in which the two sides hold clearly opposite views concerning the question of the performance or non-performance of certain […] obligations."32The Court has also said that "[w]hether there exists an international dispute is a matter for objective determination."33Establishing or denying the existence of a dispute requires more than "[a] mere assertion"34 or "mere denial".35The fact that both parties to a case agree that a dispute Thin LAPE 23 (2024)  between them exists is insufficient to establish the existence of that dispute.36The existence of a dispute is "a matter of law",37 and thus "is independent of the views or wishes of the Parties."38It is insufficient "to show that the interests of the two parties to such a case are in conflict.It must be shown that the claim of one party is positively opposed by the other."39 ITLOS has confirmed and referred to the ICJ's jurisprudence in this regard on multiple occasions.40It has also added that "the existence of a dispute may be inferred from the failure of a State to respond to a claim in circumstances where a response is called for",41 and thus that a party may not rely exclusively on its own silence in the matter to establish the absence of a dispute.42 A more recent (and controversial) development has further added to these criteria.In the Marshall Islands cases, the Court found the application inadmissible due to the absence of a dispute between the parties to the case on the basis that "it cannot be said that the [respondent state] was aware, or could not have been unaware, that the Marshall Islands was making an allegation that [it] was in breach of its obligations."43The introduction of this new "awareness" criterion has been the subject of much criticism.44Amongst these critics are those who argue that this strict treatment of the dispute requirement had less to do with law and more to do with politics, and that it reflects an attempt to avoid dealing with the politically controversial substantive aspects of the case.45 This might suggest a future side-lining of the "awareness" criterion.
However, it must be noted that this requirement has since been confirmed and applied by ITLOS on two occasions.46It seems therefore that the test will remain with us for now.
As a final point, many cases involving the definition of a dispute actually involve the application of the term "dispute" as it appears in a compromissory clause or other agreement rather than in the ICJ or ITLOS statute.47The question thus arises as to whether the term "dispute" should be understood as carrying the same meaning in both contexts.
This issue arose in CERD (Georgia v. Russian Federation), in which Russia argued that the term "dispute" in the compromissory clause in Article 22 of the Convention on the Elimination of All Forms of Racial Discrimination (CERD) "has a special meaning which is narrower than that to be found in general international law and accordingly more difficult to satisfy."48Interpreting the CERD and the use of the term therein, the Court found that "there is no reason to depart from the generally understood meaning of 'dispute' ."49It thus appeared to accept the possibility of the term carrying a different meaning, but determined that this would be for the respondent to establish.In Guyana v. Venezuela, the Court even interpreted the term "controversy" in the 1966 Geneva Agreement as a synonym for "dispute".50From these cases, it appears that the ICJ is likely to apply the same definition of dispute across the board unless there appear to be compelling reasons not to do so.
In sum, the definition of a dispute has not been uncontroversial in international law.Nonetheless, the key contours of the concept have now been confirmed in ICJ and ITLOS jurisprudence.These criteria have been used to establish whether a dispute has arisen; the following section now turns to the relationship between these criteria and the extinction of such a dispute.

2.3
The Legal Process of the Extinction of a Dispute Having established the key parameters of the definition of a dispute, this section considers the specific nature of the process of the extinction of a dispute.The key question is whether the extinction of a dispute exists as a distinct legal process in international law, with distinct legal effects.The distinctiveness of such a legal process would necessarily imply that there is a difference between the extinction of a dispute as such, on one hand, and the mere non-fulfilment of the criteria for the existence of a dispute, on the other.Consider a situation in which no dispute has arisen, and another situation in which a dispute has been resolved (and extinguished).The extinction of a dispute in the second scenario may be seen as an independent legal process if, and only if, it results in a legal situation which differs from the scenario in which no dispute had arisen.In other words, the process of extinction must change that legal situation; it must have independent legal effect.
That change or legal effect may be seen if, once extinguished, a dispute cannot re-emerge, or at least only under certain conditions which go beyond the mere fulfilment of the criteria for the definition of a dispute.This would mark a clear distinction between the situation in which the criteria for the definition of a dispute are merely absent, and the situation in which that dispute has been extinguished.It would mean that the extinction of a dispute has the legal effect of definitively resolving that dispute in such a way that it cannot simply re-emerge when the definitional criteria are met.
In sum, the extinction of a dispute may be seen as a distinct legal process if it creates distinct legal effects; and this will be the case where a dispute, once extinguished, cannot re-emerge merely by fulfilling the same definitional criteria.The following section applies these considerations to the jurisprudence of the ICJ and ITLOS in relation to the extinction of a dispute, in order to determine the extent to which it has indeed been treated as a distinct legal process.

The Extinction of a Dispute in International Law
In reviewing the jurisprudence of the ICJ and ITLOS on the extinction of a dis pute, the following sections establish three categories of ways in which a dispute may be extinguished in international law: mutual consent of the parties; authoritative resolution by a third party; and where a dispute is deprived of its object.Each is analysed with regard to the characterisation of this process of extinction as a distinct legal process with legal effects.

Mutual Consent of the Parties
Given that a dispute is essentially a disagreement between two states, it is reasonable to assume that it may be resolved by mutual consent.The question here is not whether states have reached an agreement on the existence of a Downloaded from Brill.com 09/03/2024 05:52:12PM via Open Access.This is an open access article distributed under the terms of the CC BY 4.0 license.https://creativecommons.org/licenses/by/4.0/dispute, as this question must be objectively determined.51Rather, the question is whether or not the state parties have reached an agreement on the substance of the dispute.
There are myriad ways in which states may demonstrate consent or agreement in this manner.These may be categorised into binding and non-binding forms of mutual settlement.

3.1.1
Binding Mutual Settlement Binding forms of mutual settlement include any forms of agreement which create binding legal obligations, the most obvious method of which is by treaty.The question of whether a treaty may resolve a dispute has been considered by the ICJ on more than one occasion.52In Territorial and Maritime Dispute, Colombia argued that no dispute existed between the parties because the relevant claims had been settled by prior treaty arrangements.53The Court found that the treaty in question did indeed settle the question of maritime delimitation as regards specific islands mentioned in the treaty,54 but not others.55It is therefore possible for a binding settlement to resolve a dispute definitively in this way, but whether and the extent to which it does will be a matter for treaty interpretation.
A similar situation arose in Obligation to Negotiate Access, in which Chile argued that previous treaties concluded between itself and Bolivia (amongst others) had settled the issues in dispute.56The Court concluded that the subject matter of the dispute ("whether Chile is obligated to negotiate in good faith Bolivia's sovereign access to the Pacific Ocean, and, if such an obligation exists, whether Chile has breached it")57 fell outside the scope of issues resolved by prior treaty arrangements, and therefore that it could exercise jurisdiction over the application.58 It is clear from these cases that, for the ICJ, it is possible for a treaty to settle and therefore extinguish a dispute, but whether it does will depend on the terms of the treaty.This will be determined through treaty interpretation.59There is no reason to believe that this approach would not be followed by ITLOS.60

3.1.2
Non-binding Mutual Settlement The question of non-binding mutual settlement is slightly more complex in that such forms of settlement, by definition, do not automatically generate binding legal obligations.However, their non-binding character does not necessarily mean that such forms of agreement are devoid of legal effect.61 There are a whole range of means of non-binding settlement, from negotiation to good offices, and from mediation to conciliation.62These flexible means of settlement account for the "vast majority" of attempts at dispute settlement between states.63They are often used prior to, in parallel to, or even after binding means of settlement.64 For present purposes, we are concerned with the question of whether negotiations or another form of non-binding settlement may definitively resolve a dispute and thus extinguish it as a matter of law.The fact that the parties are open to or undergoing negotiations is not in and of itself a bar to the jurisdiction of the ICJ.65 The issue is whether the dispute has already (at the time of application)66 been extinguished by such means of settlement.Despite the recognition that the existence of a dispute is an objective matter of law,67 there is unlikely to be an issue if both parties are happy with the negotiated settlement and neither understands there to be a dispute.However, the problem may arise if a settlement is negotiated but one state later changes their position, or believes that not all disputed issues were settled.
The distinction between such non-binding means and binding forms of adjudicative settlement has been famously expressed such that non-binding means essentially amounting to "substitut[ing] a series of attempts at settlement for a settlement proper."68This implies that there is no necessity nor even expectation that negotiations or similar means will lead to a definitive settlement.Given the non-binding nature of the settlement, it is reasonable to assume that the same or a similar dispute may arise once again, despite the apparent success of previous negotiations.69 Neither the ICJ nor ITLOS has ever explicitly considered whether a nonbinding negotiated settlement extinguishes a dispute, either for the purposes of establishing jurisdiction or in the application of the indispensable third party rule.The ICJ has, however, considered a similar and equivalent question in the context of discontinuance.The issue there was whether it was possible to bring proceedings after an earlier discontinuance of proceedings on the same or similar claims.70 In Barcelona Traction: New Application 1962, the Court was required to decide whether the fact that Belgium had requested (and been awarded) discontinuance of proceedings covering substantively the same claims in 196171 was a bar to the Court's jurisdiction in this Application.72Belgium had requested the discontinuance upon entering into negotiations with Spain, and had later brought new proceedings following the breakdown of those negotiations.73 The Court found that mere discontinuance of case proceedings is insufficient, on its own, to bar future proceedings being brought on the same matter;74 "giving notice of discontinuance is a procedural and, so to speak, 'neutral' act, the real significance of which must be sought in the attendant circumstances".75 The essential question is therefore "not what the discontinuance does -which is obvious -but what it implies, results from or is based on".76 In other words, it comes down to whether, in their agreement or consultations, the parties had behaved or made statements such that they had Thin LAPE 23 (2024)  renounced the right to further action.77This would be for the respondent to establish.78 Applying this reasoning to the present inquiry, it would seem that a negotiated settlement only extinguishes a dispute if the settlement itself (or the surrounding circumstances) are such that the parties may be said to have renounced the right to further action and/or to the rights attendant to the indispensable third party rule.79Assuming this is so, following the approach of the ICJ to binding settlement, a further inquiry would almost certainly need to be made to establish which specific parts of the dispute were subject to such renunciation.80The dispute would only be extinguished if and insofar as the specific claims therein had been renounced as part of the non-binding settlement.

3.1.3
Legal Effect of Extinction by Mutual Consent As can be seen in the discussion in the previous two sections, an essential element of resolution by mutual consent is that, when performed fully, it precludes further recourse to adjudication of the same issue.81 In relation to binding mutual settlement, it appears firmly accepted that a treaty may resolve a disputed issue, and that if it so does, that the particular aspect of the dispute is taken to be settled and no longer subject to the Court's or Tribunal's jurisdiction.82Similarly, non-binding mutual settlement may have an equivalent legal effect but only if and to the extent that the agreement between states amounted to a renouncement of the right to further action.83Even if one party wished to go back on the agreement, thus creating "a disagreement on a point of law or fact, a conflict of legal views or of interests between two persons",84 the operation of mutual consent serves so as to exclude the re-emergence of such a dispute.As such, the extinction of a dispute by mutual consent can indeed be seen to have a legal effect that goes beyond the mere non-fulfilment of the criteria for the definition of a dispute.

Authoritative Resolution by a Third Party
The second broad category of methods by which the dispute may be extinguished is where a decision or interpretation by a third party (thus far, at least, a judicial body) which serves to authoritatively and definitively resolve the dispute between the parties.Two forms of authoritative resolution may be seen in the jurisprudence, namely the operation of res judicata and the authoritative interpretation of the parties' claims.

3.2.1
Res judicata From first glance, it seems logical that the res judicata of international judicial decisions would (or at least could) have the effect of definitively resolving a dispute, and therefore extinguishing it.The resolution of disputes is, after all, the main purpose of international adjudication.85 The rule or principle of res judicata essentially refers to the finality of a decision or judgment by a court or tribunal.86As such, there is a clear link between this principle and the definitive resolution of a dispute.It relates to "the definitive disposition of a specific case as between the parties by a competent court."87The underlying idea is that, once a judgment has been made on a particular matter, the dispute over that matter is resolved.88From a policy perspective, this furthers both "judicial economy" and "legal security" by preventing the same issue being re-litigated, potentially with differing outcomes.89From a legal perspective, one may say that there are two sides: conclusive and preclusive.90In Ridi's words, the "conclusive" side of res judicata relates to the nature of the judgment as "final and binding upon the parties", whereas the "preclusive" side, which derives from the conclusive, means "that the matter cannot be subject to further litigation".91This is well established as a rule of law in international jurisprudence.92It has been recognised as a general principle of law,93 and is reflected in both the ICJ and ITLOS Statutes.In the ICJ Statute, Article 60 recognises the finality of ICJ judgments,94 while Article 59 recognises their binding nature -at least as far as it concerns the parties to the case.95 The restrictive approach to the revision of judgments in Article 61 also underlines this.96Article 33 of the ITLOS Statute replicates almost word-for-word Articles 59 and 60 of the ICJ Statute.97Judgments of these bodies have also recognised the res judicata effect of the decisions of other bodies, including arbitral awards.98 It has been confirmed on several occasions that the res judicata effect of a decision applies to decisions on procedural or jurisdictional matters as well as questions relating to the merits.99 The effect of res judicata is limited to the parties to the case,100 as can be seen in Article 59 of the ICJ Statute and Article 33(2) of the ITLOS Statute.101This is essentially protective of the rights of third parties.102 In order for the res judicata of a previous decision to have the effect of precluding consideration of a given case, the parties, object, and legal ground ("persona, petitum, causa petendi"103) must be the same in both the earlier case and the later case.104Provided the identity of these three elements are the same in the earlier judgment and the later case, the same dispute is deemed to be resolved and therefore may not be re-litigated.105This often reflects the main point of contention: not whether a Court or Tribunal decision is capable of resolving a dispute, but whether (and to what extent) a particular dispute was resolved by a particular decision.Certain parts of an overall dispute may be resolved by res judicata, while other parts remain contentious.This was, for example, the situation in the 2007 proceedings in Bosnian Genocide where the Court found that the earlier 1996 judgment on preliminary objections106 precluded the consideration by the Court of certain aspects of the applicant's claims, but not all of them.107 Not unlike the process of interpretation of treaties and other agreements discussed above, the adjudicative body in question must determine the scope of the res judicata effect of the earlier decision.It will therefore need to interpret the previous decision so as to determine whether the three-part test (parties, object, and legal ground; or persona, petitum, causa petendi108) is met as between the earlier decision and the present (alleged) dispute.
Thus far, the ICJ has adopted a rather narrow approach to the scope of res judicata.In the 2016 Delimitation of the Continental Shelf (Nicaragua v. Colombia) case, Colombia lodged a preliminary objection to the Court's jurisdiction based on the contention that the same issues had already been definitively resolved by an earlier 2012 judgment between the two parties.109The Court found that the three-part test was necessary but not, in and of itself, sufficient; it was deemed essential to look beyond the identity of the parties, object, and legal ground so as to further establish "the content of the decision, the finality of which is to be guaranteed"; "whether and to what extent the first claim has already been definitively settled".110The Court referred back to the Bosnian Genocide case where it has previously stated that "[i]f a matter has not Thin LAPE 23 (2024) 183-214 in fact been determined, expressly or by necessary implication, then no force of res judicata attaches to it."111 In the earlier 2012 Delimitation judgment, the Court had found that it "[was] not in a position to delimit the continental shelf boundary between Nicaragua and Colombia", largely as a result of Nicaragua's failure to provide certain information to the Commission on the Limits of the Continental Shelf (CLCS) (as it had been required to do).112 Colombia read this finding as a rejection by the Court of Nicaragua's claim related to the continental shelf.113Nicaragua, by contrast, argued that this was merely a refusal to rule on its claim, and therefore that the dispute had not been yet resolved.114 The Court ruled in favour of Nicaragua on this point.115It found that it was not precluded by the res judicata principle from ruling on the new application submitted by Nicaragua because the dispute had not been definitively resolved by its prior judgment.116This was highly controversial even amongst the bench: this was one of the rare occasions where the judges were split and the President's casting vote was required.117 The finding was strongly criticised in dissenting opinions by the minority.They pointed out that it essentially gave Nicaragua a second chance to remedy its own failure to provide information to the CLCS,118 and warned that reading res judicata too narrowly "undermines the judicial function";119 that it could "undercut the certainty, stability, and finality that judgments of this Court should provide."120Despite this criticism, it would appear that the ICJ has opted to continue a relatively narrow approach to the scope of res judicata in Arbitral Award (Guyana v. Venezuela) (Preliminary Objections).In a previous set of proceedings (in which Venezuela refused to participate),121 the Court found that it had jurisdiction to hear the case based on the 1966 Geneva Agreement between the parties.122Despite this, Venezuela then submitted a preliminary objection to the effect that the UK was an indispensable third party in the case and therefore that the case was inadmissible.123Guyana argued that this preliminary objection itself should be found inadmissible because the Court had already made a definitive decision on questions of jurisdiction.124They argued that it was "a thinly disguised attack on the Court's Judgment, … a misguided attempt to persuade the Court to revisit and revise that Judgment",125 and that to entertain Venezuela's objection would violate the principle of res judicata.126 Applying once again a rather narrow approach to the scope of res judicata, the Court drew a distinction between matters related to the "existence of jurisdiction", and those related to the "exercise of jurisdiction", i.e. admissibility.127 It then held that the application of the indispensable third party rule fell into the latter and therefore remained unresolved by the earlier judgment.128According to the Court, "the force of res judicata attaching to the 2020 Judgment extends only to the question of the existence and not to the exercise of jurisdiction".129Venezuela's objection was thus held to be admissible.130 Both judgments demonstrate a relatively restrictive approach to the scope of res judicata by the ICJ.In both cases, there may be strong reasons of judicial policy that led the Court to act in the way it did.With regard to Delimitation of the Continental Shelf, for example, Ridi argues that the "complex circumstances" surrounding that case, including the outstanding question of Nicaragua's maritime border with other UNCLOS member states, and related "concerns of consistency and coherence" could have led to and warranted such an approach.131Similarly, in Arbitral Award, the Court may have taken such an Thin LAPE 23 (2024)  approach in an attempt to reward or encourage the renewed participation of Venezuela in the proceedings.132 There is relatively limited discussion in ITLOS of the res judicata of previous binding decisions, although it has recognised that a binding arbitral award could have such an effect.133There is no explicit evidence that ITLOS would depart from such an approach.However, the ICJ's restrictive approach towards res judicata may be contrasted against ITLOS' much less restrictive approach towards the legal effect of authoritative interpretation of parties' claims.134

3.2.2
Authoritative Interpretation of the Parties' Claims A new candidate for the extinction of disputes entered the fray relatively recently with the 2021 ITLOS decision on preliminary objections in the Dispute concerning the delimitation of the maritime boundary between Mauritius and Maldives.135 The maritime delimitation at the centre of this case is complicated by the location of the Chagos Archipelago, over which there has long been a territorial dispute between Mauritius and the UK, in the disputed region.Based on this (alleged) dispute, the Maldives lodged preliminary objections to the effect that, in accordance with the Monetary Gold rule, there was an ongoing territorial dispute between the UK and Mauritius over the Chagos Archipelago, and therefore that ITLOS would be barred from exercising jurisdiction over the case.136Mauritius argued, inter alia, that this dispute with the UK had been resolved by the ICJ's earlier Advisory Opinion, and therefore that it had been extinguished and the Monetary Gold rule did not apply.137before the International Court of Justice", 16 The Law and Practice of International Courts and Tribunals (2017), 224, 242-243, who argues that the de facto re-consideration of Nicaragua's claims was undertaken due to an attempt to remedy supposed insufficient reasoning in the previous judgment.132 Sarah  The Special Chamber held in favour of Mauritius on this point.It found that advisory opinions of the ICJ are "authoritative" despite not being binding,138 and that as such the ICJ's earlier Opinion had "clarified" the legal status of the Chagos Archipelago.139Therefore, "the continued claim of the United Kingdom to sovereignty over the Chagos Archipelago cannot be considered anything more than 'a mere assertion'", not a true dispute.140Thus, the "authoritative interpretation" of the law by the ICJ had, in the Chamber's opinion, been such as to definitively resolve and therefore extinguish the dispute between the UK and Mauritius.141 In support of this approach, the Chamber cited the South West Africa cases and the definition of a dispute given there, specifically the ruling that a dispute must be based on more than a "mere assertion".142This would seem to be a rather twisted application of that jurisprudence given that the focus in the South West Africa cases and subsequent decisions has always been on whether the two states are actually in disagreement (which is clearly the case between the UK and Mauritius), not a qualitative assessment of one side's position (as the Special Chamber seems to suggest here).143As Judge Oxman notes in his Dissenting Opinion, these reflect two quite distinct functions behind the application of the term "dispute".144 The Chamber also referred to a number of judgments by other bodies, including the Court of Justice of the European Union, in which ICJ advisory opinions have been found to represent authoritative interpretations of the law.145However, the important distinction is that, unlike in those cases, the Chamber did not apply the law as stated by the ICJ in its Advisory Opinion, thereby resolving the dispute between the UK and Mauritius.Indeed, it would not have had the jurisdiction to do so.Instead, the Special Chamber deemed Thin LAPE 23 (2024) 183-214 the dispute already resolved; it held that it had been legally concluded by a (non-binding) advisory opinion.146 In addition to the surprising conclusion that advisory opinions have such a "legal effect",147 the broad interpretation of the scope of this effect is at odds with the ICJ's approach to res judicata discussed above.Both the operation of res judicata and authoritative interpretation essentially amount to the definitive and authoritative resolution of a dispute by a third party.One would thus expect that the restrictive approach taken to the scope of res judicata should be applied a fortiori to cases of mere authoritative interpretation.The approach taken by the Tribunal, however, cannot be described as restrictive.At best, the relevant parts of the ICJ's Opinion148 only imply that the UK's territorial claim over the Archipelago has been found to be void, in favour of Mauritius' claim.Indeed, it is arguable that the ICJ specifically and "carefully avoided pronouncing directly on the sovereignty issue."149The Court even explicitly says in its Opinion that "[t]he General Assembly has not sought the Court's opinion to resolve a territorial dispute between two States".150Although the ICJ has previously recognised in the abstract that "necessary implication" could be sufficient for the force of res judicata to resolve a dispute,151 the broad-brush approach of the ITLOS to the effect of this Opinion is in strong contrast with the ICJ's narrower approach to the scope of res judicata, especially in the Delimitation case between Nicaragua and Colombia.152 It is possible that this judgment is also a policy-based reaction to the moral imperative of ending colonialism in the Chagos region.153This is a singular case and it is not yet clear whether this approach to authoritative interpretation will be followed, either by the ITLOS or by the ICJ.
It is also unclear whether this standard and legal effect might be applied to decisions or opinions of other bodies.Human rights treaty bodies have at times been described as providing "authoritative" interpretations of the legal rules within the remit of their particular treaty.154It might be arguable on the basis of this ITLOS judgment that these could also have the result of extinguishing a dispute.On the other hand, it may be said that the ICJ's "institutional authority" was a key factor in this case,155 which would suggest otherwise.The exact implications of the ITLOS' decision for the extinguishment of disputes will become clear over time, but for now at least it is fair to say that it remains somewhat an outlier.

3.2.3
Legal Effect of Authoritative Resolution Similar to the application of mutual consent as discussed above, the authoritative resolution of a dispute by a third party can be seen to definitively extinguish a dispute.156As was discussed above in relation to res judicata, this process has both conclusive and preclusive effect, both resolving an issue and precluding further recourse to legal action.157Thus, res judicata as a means of dispute extinction has legal effects distinct from the application of criteria for the definition of a dispute; differences in views may remain,158 but the resolution by the third party effectively prevents the re-emergence of the dispute from a legal perspective.
The Mauritius v. Maldives case suggests that ITLOS is willing to extend this type of legal effect to authoritative interpretation of a party's claims, at least in certain circumstances.159 The finding in that case was that the dispute between the UK and Mauritius was definitively resolved and thus extinguished, not that it failed to meet the criteria for a definition of a dispute.160 It remains unclear at this point how far this doctrine of authoritative interpretation as a method of extinction of disputes will be taken, including by other adjudicative bodies.Nonetheless, it is apparent that the resolution of a dispute by a third party does indeed have a distinct legal effect, creating a new legal situation whereby the re-emergence of a dispute is precluded.It thus amounts to a distinct legal process of extinction of a dispute.

3.3
When a Dispute Becomes "without Object" 3.3.1 Disappearance of the Object of the Dispute The final candidate for extinction of a dispute is the situation that occurs where the dispute itself essentially becomes "moot".161 In other words, a dispute may be rendered "without object"162 due to changing circumstances which defeat the purpose of the proceedings.It is not unheard of that parties themselves discontinue proceedings on this basis.163Such circumstances as these are not unlike the situation discussed in Section 3.1.2where both parties operate on the understanding that there is no dispute or no need to invoke one following a non-binding agreement.The situation is different, of course, where one or more of the parties does not agree that the object of the dispute has been removed.
In the Nuclear Tests cases, the Court found that the dispute at hand had ceased to exist because Australia's and New Zealand's objective in bringing the case (namely the cessation of nuclear testing by France) had been met by France's declaration that this testing would cease.164This was a controversial conclusion, not least because it involved interpreting Australia's and New Zealand's "objective" in a way which appeared to be contrary to their explicit wishes.165Australia and New Zealand certainly seemed to believe that such a dispute continued to exist, regardless of France's declaration; as the Court itself noted, if they believed the dispute to be concluded then they themselves could have discontinued proceedings, which they did not.166The majority's view that there was no longer a dispute was strongly opposed by certain judges who argued that the "object" of Australia's and New Zealand's claims was not simply the cessation of nuclear testing, but that there was a dispute over the legality of the testing in the first place.167 For a time, it seemed as though the notion that a dispute may be extinguished if it is rendered "without object" was to be left to the history books.In no other case was it found that a dispute had ceased to exist in this manneruntil, that is, the doctrine was reawakened in the 2022 ICJ case between Chile and Bolivia concerning the Silala watercourse.168 The Silala case began, as did Nuclear Tests, with a clear dispute over a number of different claims between the parties.169However, by the time the Court was called upon to render a judgment, Bolivia's position had changed significantly, such that the difference between the claims of the two parties was greatly reduced.170Referring back to Nuclear Tests, the Court emphasised that "[t]he dispute brought before it must … continue to exist at the time when the court makes its decision" and that this would not be the case "where the object of a claim has clearly disappeared".171This was held to be an inescapable aspect of the Court's contentious judicial function.172Accordingly, it was necessary to decide whether "specific claims have become without object as a consequence of a convergence of positions or agreement between the Parties, or for some other reason."173The Court found that, as a result of this "convergence",174 a large part of the dispute "no longer ha[d] any object".175Of Chile's five claims and Bolivia's three counter-claims, six were held to be inadmissible for this reason.176 This equation of the convergence of parties' claims with the rendering of a claim as "without object" is new and certainly not free from controversy.In her Declaration appended to the decision, Judge Charlesworth argued that this is a distinct application of the concept of "without object" compared to that which was discussed in the Nuclear Tests cases.177 In Nuclear Tests, the Court first identified the specific objective of the claimants (interpreted by the Court as the cessation of nuclear testing) and found that it had been achieved.In Silala, by contrast, the Court did not identify such an objective but rather made a finding Thin LAPE 23 (2024)  that the convergence of the views of the parties had resulted in the disappearance of the dispute itself.178As Charlesworth writes of the Silala case, there "is no indication in the Judgment that the object of any claim or counter-claim has been achieved by other means, or specifically that an intervening act had a similar effect to that of France's unilateral undertakings in Nuclear Tests".179 Beyond the question of whether the convergence of parties' arguments can serve so as to remove the object of the dispute is the question of which elements have been so extinguished -i.e. the question of interpretation.One of the controversial aspects of the Court's reasoning in Silala was whether the parties' arguments had actually converged to the point where the difference between them was so insignificant as to render a judgment on that point unnecessary or "devoid of purpose".180Both Judges Simma and Charlesworth criticised what they called the "impressionistic approach"181 of the Court in interpreting the parties' claims and the extent to which they converged.This "slippery interpretation"182 seems to have allowed the Court to overlook certain differences that did remain between the submissions of the parties.For example, while both parties recognised that the Silala is an international watercourse, key differences remained relating to the definition thereof and the application of the principle of equitable and reasonable utilisation to the particular circumstances of this case.183This relaxed approach to interpretation seems to contrast with the stricter interpretation applied by the Court in relation to mutual settlement and res judicata, as discussed above.

3.3.2
Legal Effect of the Disappearance of the Object of a Dispute The Court's approach in this area has not been uncontroversial.A similar doctrine has not yet been applied by the ITLOS, and as yet it is unclear whether the same path will be followed.Despite the controversy surrounding this jurisprudence, it is worth considering how if at all it fits within this broader notion of the extinction of a dispute.
At first glance, one may doubt whether this doctrine of the disappearance of the object of a dispute is indeed a form of extinction, rather than a new aspect of definition of a dispute or even a new admissibility requirement more generally.One could interpret this line of cases as merely adding an additional requirement that a dispute or claim is not "devoid of purpose".184The key question, as discussed above, is whether the finding that "the object of a claim has … disappeared"185 has the additional legal effect of precluding the re-emergence of the same dispute.
In Nuclear Tests, the dispute was rendered "without object" by an intervening act, namely the unilateral statement of France, whereas in Silala it was the convergence of the parties' claims due to Bolivia's altered position that was at issue.186In both cases, therefore, it was a unilateral act of one state (France's statements, and Bolivia's alteration of their claims) that resulted in the removal of the object of the dispute.The legal nature of this unilateral act is therefore key.
In Nuclear Tests, the Court preceded its finding that France's statements had removed the object of the dispute with a finding that these unilateral acts were capable of creating binding international legal obligations.187The Court's judgment also refers to the potential of such statements to "resolve" a dispute.188Given that the unilateral act was recognised as having legal effect -as being capable of changing the legal situation so as to create binding obligations -it is indeed possible to read this intervening act as resolving and therefore extinguishing the dispute at hand.Should France have failed to comply with the obligations arising from its unilateral act, then a new dispute may have emerged, but one based at least in part on this new legal relationship between the parties and therefore not simply a re-emergence of the old dispute.
The convergence of the parties' claims in Silala is different in that there was no explicit consideration by the Court as to whether Bolivia's alteration of its claims had had legal effect, or had created a new legal situation.
The key issue here is whether, analogous to France's unilateral act in Nuclear Tests, Bolivia would be bound in some manner by its altered position.The failure of the Court to pronounce on the legal force of the points of agreement between the parties has been subject to criticism.189Judge Simma warned in his Separate Opinion that it sends "the signal that any position may be held, however untenable, so long as this position is abandoned at the 11th hour of the judicial proceedings".190Nonetheless, if Bolivia's alteration of its claims does indeed have legal effect in the sense that the state would then be bound to that new position, this could be seen as a form of extinction of a dispute by unilateral act, analogous to Nuclear Tests.
Overall, the limited jurisprudence and the controversy surrounding that case law makes it difficult to draw firm conclusions with regard to the extinction of a dispute by rendering it "without object".However, this section has established that at least one possible reading of this doctrine is that a unilateral act by a state may resolve a dispute by removing the object of that dispute, creating a new legal situation between the parties.Taking this into account, the removal of the object of a dispute may be considered alongside mutual consent and authoritative resolution by a third party as a possible means of extinction of a dispute, where the latter may be understood as a distinct legal process with legal effects.The following section explores the relationship between the extinction of a dispute and the broader framework of international law, linking it to the international judicial function.

4
The Extinction of a Dispute and the International Judicial Function Taking a more systemic view on the extinction of a dispute, how does this legal process fit within the broader framework of rules and principles related to international adjudication?What role does it play in the international legal order?In the cases discussed above, reference is often made to the international judicial function, particularly the contentious function of international courts and tribunals.191It was noted in the introduction to this article that disputes are central to international law and international adjudication; that the primary purpose of international adjudication is the pacific settlement of disputes.192Thus, a core aspect of the international judicial function is the resolution of disputes; the ending of disputes.This function is closely linked to the principle of legal certainty and the international rule of law.193These principles are clearly reflected in the three methods of extinction of a dispute discussed above.With regard to mutual consent, it flows from both aforementioned principles that the outcome of a legally binding, legally valid settlement has the force of law and attendant legal effect -in this case, the resolution of any pre-existing dispute that is the subject of the agreement.It similarly flows from the principle of legal certainty that if two states make a binding legal agreement between themselves concerning particular topics of contention, no valid legal dispute may exist on the points that have been so agreed.To find otherwise would be to destabilise the force of law inherent in the rule of law and undermine legal certainty.This also helps to explain why binding mutual settlement enjoys greater acceptance than non-binding settlement as a means of extinguishing a dispute.194Non-binding agreements do not carry the force of law, nor are they subject to expectations of legal certainty.Nonetheless, in certain specific circumstances, it may be that such non-binding agreements are made in a context wherein the states in question renounce the right to further action, thus essentially leading to the extinction of the dispute.195This remains a possibility which could still be seen to contribute to certainty within the international legal sphere.
A similar relationship may be seen between these principles and the second method of extinction identified in this article, namely authoritative resolution by a third party.Both the operation of res judicata and the authoritative interpretation of the parties' claims essentially relate to the ability of a third party to authoritatively resolve and thus extinguish a dispute.This may also be seen to stem from similar principles: the rule of law and force of law of the decisions of international courts and tribunals; the principle of legal certainty Thin LAPE 23 (2024) 183-214 relation to the same.196However, while the operation of res judicata is clear and remains relatively unquestioned, the ability of an authoritative interpretation to extinguish a dispute remains controversial.197 Authoritative interpretation is further removed from the core contentious judicial function and the binding nature of judicial decisions than res judicata.As such, it may be seen as resting upon a weaker foundation.Other principles or interests may of course come into play.One could read ITLOS' approach in Mauritius v. Maldives as being reflective of the community interest in the subject matter of the case itself -namely decolonization.198While a traditional approach to the judicial function may be more purely focused on dispute settlement,199 some modern interpretations of the role of international courts and tribunals accord greater space to their role as guardians of the international community interest.200ITLOS' finding that the dispute between Mauritius and the UK had been extinguished allowed it to exercise jurisdiction over the case between Mauritius and the Maldives (despite the operation of the Monetary Gold rule).201This could therefore be interpreted as a balancing act between the community interest in hearing that case and the more traditional, certainty-based approach to the concept of a dispute.Time will no doubt tell whether such an approach will continue to be followed, and whether the international community interest will play a greater role in the application of the law on the extinction of disputes.
Finally, the third method of extinction (the disappearance of the object of the dispute) may also be seen to be based upon legal certainty and related principles in international law.The interpretation of the jurisprudence advanced above whereby the dispute in both cases was resolved by a unilateral act with legal effect essentially advances the notion that commitments made by states must be adhered to.In Nuclear Tests, the Court emphasised that "[o]ne of the basic principles governing the creation and performance of legal obligations, whatever their source, is the principle of good faith."202The Court underlined that, analogous to the rule of pacta sunt servanda, where a state commits to certain conduct by way of a binding unilateral declaration, other states may be entitled to rely on and to require compliance with that declaration.203As such, the legal effect of the extinction of disputes via this method is based upon the interest in ensuring and respecting the force of law of such commitments.
It can be seen from the above that each of these methods of extinction of a dispute form a close link between this legal process and principles related to legal certainty, good faith, and the rule of law.Each of these, in turn, form core aspects of the international judicial function and the role that international courts and tribunals play within the international legal order.The legal effect of the extinction of a dispute is therefore rooted in the essential nature of international adjudication.It builds from and is intrinsically connected to these fundamental, underlying foundations of the international legal system.It is more than simply a question of definition, but rather an unavoidable and essential legal process at the heart of dispute settlement.

Conclusion
Disputes arise between states, and when they do, they can have serious consequences.This is a large part of why international law has developed and evolved.International adjudicative mechanisms exist as an alternative to other, less peaceful forms of dispute settlement.This paradigm assumes that there is a lifecycle at play: that disputes emerge, but that they may also be concluded.As with all things in law, it is crucial to have clear criteria for identifying when this legal process -the extinction of a dispute -has taken place, and how, precisely, it works.This article has provided a detailed analysis of the legal terrain surrounding the extinction of disputes in international law, a subject thus far underexplored in the literature.Drawing from the jurisprudence of the ICJ and ITLOS, it identified three methods by which a dispute may be extinguished as a matter of law: (1) mutual settlement between the parties; (2) authoritative resolution of the disputed issue by a third party; and (3) the removal or disappearance of the object of the dispute, specifically by means of a unilateral and legally effective act by one party.Each of these methods may be seen to have led to the definitive resolution and thus extinction of the dispute in question.Through this analysis, it has been established that the extinction of a dispute constitutes a distinct legal process with legal effect, a separate question from the mere fulfilment or non-fulfilment of the criteria for the definition of a dispute as such.
The legal process of the extinction of disputes has also been shown to be deeply rooted in fundamental principles of international law.It reflects the essential nature and purpose of international adjudication and its role in the pacific settlement of disputes.The role of international courts and tribunals in resolving disputes is inextricably linked with their role in ending disputes.Each of the three methods identified in this article can be sourced back to foundational legal principles stemming from the international rule of law.
The extinction of disputes, as a matter of international law, has not always been clear, but it has always been an essential part of the international judicial function.This article has clarified, distinguished, and situated this legal process in the international legal order.It has sought to give recognition to the singular place that the extinction of disputes occupies in international law, and to demonstrate that international law does indeed account for the end of the affair.