1.1. A brief introduction to Article 60 of the ICJ Statute

Article 60 of the ICJ Statute reads as follows: ‘The judgment is final and without appeal. In the event of dispute as to the meaning or scope of the judgment, the Court shall construe it upon the request of any party’. Article 60 thus consists of two separate but interrelated parts. The first sentence enshrines the formal aspect of the res judicata principleFootnote ¹ – the Court cannot consider the same matter again in a new proceeding and the Statute does not provide for any appeal mechanisms.

It is widely accepted that there are ‘three traditional elements for identification [of res judicata], persona, petitum, causa petendi’.Footnote ² For a prior decision to qualify as res judicata in public international law there must be identity of the parties to the dispute and identity of the question, the latter falling into object or relief (petitum) and grounds (causa petendi).Footnote ³ However, if the grounds are identical, international tribunals have sometimes been generous about the identity of relief requirement and have denied claimants to seek different relief on the same grounds.Footnote ⁴ By contrast, in the Haya de la Torre case the ICJ denied res judicata effect of the earlier Asylum case because it considered the question before the Court in Haya de la Torre a new one, i.e., dealing with the surrender of Mr. Haya de la Torre rather than the question of whether granting him diplomatic asylum was illegal.Footnote ⁵

As oneFootnote ⁶ instrument to remedy the absence of an appeals mechanism, the second sentence of Article 60 of the ICJ Statute contains instead the possibility for the parties to seize the Court to interpret its judgments. Such interpretation proceedings are indeed a seemingly odd companion of original contentious proceedings in international arbitration and litigation that owes its existence to the principle of finality of international judgments and awards. In domestic litigation, where there is usually an appeal mechanism, interpretation proceedings are mostly unknown. However, on the international level, we find provisions similar to Article 60 of the ICJ Statute in sources as diverse as Article 33(3) of the Statute of the International Tribunal for the Law of the Sea (ITLOS),Footnote ⁷ the compromis in the Channel Arbitration between the United Kingdom and France,Footnote ⁸ or Article 50 of the Convention on the Settlement of Investment Disputes between States and Nationals of Other States (ICSID Convention). All these provisions have in common the fact that the court or tribunal's judgment or award is intended to be the last word on the dispute.

While an interpretation must not constitute an appeal, it nonetheless fills the void that the absence of an appeal mechanism creates: A decision, as well crafted as it may be, might leave the parties with open questions as to its ‘meaning and scope’, especially over the course of time.Footnote ⁹ Hence the need to seize again the same bodyFootnote ¹⁰ that delivered the decision to explain how the parties should understand the final decision with regard to issues that remained opaque. However, here, the relationship between interpretation and res judicata – i.e., in the context of the ICJ Statute, the relationship between the first and the second sentences of Article 60 – comes into play. What the Court has decided with binding force is the beginning and end of any interpretation proceeding. As Andreas Zimmermann puts it, interpretation is ‘a procedure of clarification’, whose aim is ‘not the questioning of the findings of the original judgment, but rather instead the confirmation of its res judicata effect’.Footnote ¹¹

An interpretation proceeding thus may not somehow mutate into a disguised appeal. Keeping this premise in mind is particularly important considering that Article 60 does not contain any time limits for submitting a request for interpretation.Footnote ¹² Such a request may even be introduced if the parties are no longer subject to the Court's jurisdiction.Footnote ¹³ As the Permanent Court of International Justice (PCIJ) had already found regarding proceedings under the identically-worded Article 60 of the PCIJ Statute, an interpretation decision may only clarify an earlier judgment within the confines of what the Court has already decided with res judicata effect: ‘The interpretation adds nothing to the decision, which has acquired the force of res judicata, and can only have binding force within the limits of what was decided in the judgment construed’.Footnote ¹⁴

The second sentence of Article 60 of the ICJ Statute sets forth two requirements. There needs to be (i) a ‘dispute’ as to (ii) the ‘meaning and scope’ of an earlier judgment of the Court. The jurisprudence of the Court usually identifies these as requirements to the admissibility of the claim, e.g., in the Asylum, Continental Shelf, Land and Maritime Boundary, and Avena cases,Footnote ¹⁵ as did the PCIJ in the Chorzów Factory case.Footnote ¹⁶ In the recent Temple case interpretation judgment,Footnote ¹⁷ the Court appears to have deviated from such a practice, discussing these requirements as questions of the ‘jurisdiction of the Court under Article 60 of the Statute’,Footnote ¹⁸ without providing any support for this change in view. In my opinion, whether there is a ‘dispute’ regarding the ‘meaning and scope’ of an earlier judgment of the Court is not a question of the correct forum. Rather, the question before the Court is whether, being before the competent forum, the requirements are fulfilled to proceed to the merits, i.e., one of admissibility rather than of jurisdiction.Footnote ¹⁹

While the ‘meaning and scope’ leads us back to the confines of what has been decided with binding force,Footnote ²⁰ a ‘dispute’ requires a ‘divergence of views’Footnote ²¹ on what the Court has decided with res judicata effect in its original judgment, i.e., on ‘definite points’.Footnote ²² As the Court has emphasized in the Asylum case, ‘one cannot treat as a dispute … the mere fact that one Party finds the judgment obscure when the other considers it to be perfectly clear’.Footnote ²³ However, the dispute does not necessarily need to have manifested itself in express form or in a formal way, e.g. by exchange of diplomatic notes.Footnote ²⁴ ‘[I]t should be sufficient if the two Governments have in fact shown themselves as holding opposite views in regard to the meaning or scope of a judgment of the Court’.Footnote ²⁵

1.2. The 2013 Temple case: Facts,Footnote ²⁶ the original judgment of 1962, and its interpretation by the Court in its judgment of 11 November 2013

In 1904, Siam (now Thailand) and French Indochina (now Cambodia) concluded a boundary treaty that entrusted a Mixed Commission with the task of surveying the border area and creating maps on the basis of which the two parties to the treaty would decide on the eventual boundary. The Mixed Commission created eleven maps, including the so-called Annex I map, which included the area surrounding the Temple of Preah Vihear, the bone of contention, and which ‘show[ed] the whole Preah Vihear promontory, with the Temple area, as being on the Cambodian side’ of the border.Footnote ²⁷

The Siamese government received the maps, including the Annex I map, in 1908. While it did not give a sign of formal acceptance, it requested copies of these maps from the Mixed Commission and, over the course of almost fifty years, did not raise any concerns regarding the delimitations made in the maps with the Commission or the French authorities. By contrast, the French representative received an official Thai delegation on the Temple premises with the French flag flying on the grounds and without the Thai officials protesting. In the words of the Court in its original judgment of 1962: ‘A clearer affirmation of title on the French Indo-Chinese side [than hoisting the flag on the premises] can scarcely be imagined. It demanded a reaction. Thailand did nothing’.Footnote ²⁸ Accordingly, the Court held that Cambodia, which had gained independence in 1953, exercised territorial sovereignty over the Temple and that Thailand was ‘under an obligation to withdraw any military or police forces, or other guards or keepers, stationed by her at the Temple, or in its vicinity on Cambodian territory’.Footnote ²⁹

The conflict over the Temple arose anew in 2007. Cambodia applied for inclusion of the Temple in the UNESCO world heritage list and submitted a map together with the application that indicated the Temple and the promontory of Preah Vihear, as well as the hill of Phnom Trap, as Cambodian territory. Thailand protested immediately against the delimitation in the map and sent its troops to occupy the Temple's surroundings.Footnote ³⁰ In view of several armed clashes between Thai and Cambodian troops in the Temple area, both the UN Secretary-General and the UN Security Council called upon Thailand and Cambodia to commit to ‘a permanent ceasefire’, which, however, did not lead anywhere.Footnote ³¹ Eventually, on 28 April 2011, Cambodia seized the Court to interpret its 1962 judgment and the Court delivered an order on provisional measures in July 2011 and its judgment in November 2013.

The elements of the 11 November 2013 judgment most enlightening for the purpose of the present study pertain largely to the discussion on the merits. As regards issues of jurisdiction and admissibility, suffice it here to mention the Court's analysis with regard to whether there was a ‘dispute’ between Cambodia and Thailand concerning the interpretation of the original judgment of 1962. Citing its earlier case law, the Court,Footnote ³² stated that:

while at the same time referring to ‘essential’ reasons in the Court's decision as to what forms part of the ‘dispute’ in question.Footnote ³⁴ I will revisit this matter, which pertains to how much of the reasoning of the original judgment should be considered res judicata – and thereby subject to interpretation in Article 60 proceedings – and which is at the very centre of this contribution, in section 2.2. below.

The Court, with regard to the interpretation of the 1962 judgment, underlined again the confines set by the res judicata of the original judgment. However, it nevertheless acknowledged a certain degree of flexibility in its approach as to the interpretation of the ‘dispute’ among the parties. As the PCIJ had already determined in the Chorzów Factory case:

Due to such flexibility, the Court may, in its exercise to determine meaning and scope of the dispositif of the original judgment, ‘have regard to the reasoning of that Judgment to the extent that it sheds light on the proper interpretation of the operative clause’.Footnote ³⁶ While this may sound like a broader standard than focusing merely on a reasoning ‘inseparable’ from the dispositif, the subsequent interpretation, as demonstrated below, nonetheless remained within the confines of the narrower standard. Furthermore, the Court may consult the parties’ pleadings and the record of the oral proceedings in the original judgment.Footnote ³⁷

It went on to interpret the second paragraph of the operative part which was at the centre of the ‘dispute’ between the Parties and which read as follows:

What did the Court hence mean by ‘vicinity’ of the Temple? It commenced its interpretation by examining the evidence before it in the original judgment regarding the location at which the Thai personnel mentioned in the dispositif were stationed. According to Thailand's witness and expert in the original proceedings, during his visit to the Temple in July 1961 in the course of preparing his report, the only people he had seen at the Preah Vihear promontory were a detachment of Thai frontier police and one Temple guard.Footnote ³⁹ The Thai frontier police had been stationed north of a line that the Thai Council of Ministers drew by resolution immediately following the 1962 judgment and thus outside what Thailand, in the interpretation proceedings, considered to be the ‘vicinity [of the Temple] on Cambodia territory’.Footnote ⁴⁰ The Court found that this fact resounded in the second paragraph of the operative clause:

Thus, to the Court, the ‘vicinity’ of the Temple stretched at least to where the police detachment was stationed and went beyond the line viewed by Thailand to represent the territorial scope of the dispositif.

The geographic location and features of the Temple and its surroundings confirmed such reading:

Such geographic location and features of the area around the Temple, however, led the Court to exclude from the Temple's ‘vicinity’ the hill of Phnom Trap.Footnote ⁴³ ‘Phom Trap and the promontory of Preah Vihear are distinct geographical features which are clearly shown as separate on the maps used in the 1962 proceedings.’Footnote ⁴⁴ This again was supported by the evidence before the Court in the original proceedings.Footnote ⁴⁵ This reading of ‘vicinity,’ which included the promontory of Preah Vihear but excluded the hill of Phnom Trap, in the eyes of the Court was a general and coherent one employed throughout the whole judgment of 1962 and thus underlying the other paragraphs of the operative parts of the original judgment.Footnote ⁴⁶

2.1. Res judicata in public international law: Functions, concepts, case law

The principle of res judicata aims at finalization. It brings to an end, and thereby serves to ‘settle’ an international dispute. The authority of international adjudication, and thus eventually of international law, derives from, or at least depends on, the finality of an international award or judgment. If the same dispute or the same or similar issue can be re-litigated before the same court or tribunal, or, which has the same effect, if the scope and limits of an interpretation of such award are stretched beyond what the court or tribunal had decided in the original judgment with binding force, the parties will lose faith in the viability of international adjudication as the appropriate means to settle international disputes.Footnote ⁴⁷

Therefore, avoiding re-litigation is not an end in itself. Its purpose is legal securityFootnote ⁴⁸ (Rechtsfrieden) and, eventually, the maintenance of international peace. As we are constantly reminded by numerous international conflicts that do not end up before an international court or tribunal, international legal dispute settlement by international adjudication is only one among several means of international dispute settlement that a state may resort to.Footnote ⁴⁹ Caldeira Brant underlines such a link between the principle of res judicata and the maintenance of international peace:

In respect of the International Court of Justice, Article 2(3) read together with Article 92 of the UN Charter and Article 1 of the Statute of the Court emphasizes such a relationship between the role and function of the Court in the international arena and the peaceful settlement of international disputes. As Shabtai Rosenne puts it, ‘the Court has a task that is directly related to the pacific settlement of international disputes and therefore to the maintenance of international peace’.Footnote ⁵¹ The Temple case is a perfect example of the potentially devastating consequences a decision by an international court may have if it remains unclear what has actually been settled with binding force, and of how close the connection between res judicata and the maintenance of international peace in fact is.Footnote ⁵²

Let us move to the ‘crucial question’: ‘what parts of an award [or judgment] have the binding force of res judicata’Footnote ⁵³? The scope of res judicata defines which parts of a judgment may not be re-litigated as well as which parts are subject to interpretation by the body that had delivered the original judgment or award. The central issue, that also arose in the Temple case, is, as David Bowett put it, ‘whether the dispositif … alone is binding, or whether the essential reasoning on which those findings rest is also res judicata’.Footnote ⁵⁴

In the Temple interpretation judgment of 11 November 2013 the matter resounded in the joint declaration of Judges Owada, Bennoua, and Gaja, and the separate opinion of Judge Cançado Trindade. Judges Owada, Bennoua, and Gaja observedFootnote ⁵⁵ that the Court, when drawing the lines of what it considered res judicata for the purposes of interpretation pursuant to Article 60 of the ICJ Statute, referred indiscriminatelyFootnote ⁵⁶ to earlier ICJ case law which predominantly considered only those parts of the motifs subject to res judicata that are ‘inseparable’ from the dispositif,Footnote ⁵⁷ as well as to the PCIJ in the Chorzów Factory interpretation judgment, which included all ‘essential’ reasons within the scope of res judicata.Footnote ⁵⁸ However, ‘inseparable’ reasons are not the same as ’essential’ reasons.Footnote ⁵⁹ ‘Inseparable’ are those reasons without which the operative part cannot stand,Footnote ⁶⁰ while ‘essential’ are reasons on which the substance of the legal reasoning is based that, in turn, crystallizes in the operative part. Thus, ‘inseparable’ is mostly a formalistic, narrow criterion, whereas ‘essential’ is normative and potentially much broader.

In contrast to Judges Owada, Bennoua, and Gaja, Judge Cançado Trindade, in his separate opinion to the interpretation judgment in the Temple case, thought that both the dispositif and the motifs in their totality should form part of the res judicata of a prior judgment because, ‘[i]n effect, to my mind, motifs and dispositif form an organic, inseparable whole’.Footnote ⁶¹

Such difference in approach as to the scope of res judicata takes us back to the origins of the doctrine in domestic law.Footnote ⁶² As the Interim Report ‘“Res Judicata” and Arbitration’ of the International Law Association (ILA) at the 2004 Berlin Conference fleshed out so pertinently, the narrower and wider understandings of res judicata have their roots in the civil law and common law traditions respectively.Footnote ⁶³

Common law jurisdictions, where res judicata are treated as a type of the doctrine of estoppel,Footnote ⁶⁴ prefer the broader approach. In English common law, the relevant ‘issue’, regardless whether of fact or law, must constitute an ‘essential element in the cause of action or defence. … [E]lements of the reasoning and not just the formal order may give rise to res judicata’.Footnote ⁶⁵ All ratio decidendi is thus subject to ‘issue estoppel’, merely the obiter dicta do not form part of it.Footnote ⁶⁶ Similarly, in the United States, the ‘issue’ at hand must be ‘essential to the judgment’. This means that ‘the appropriate inquiry is whether the issue was actually recognized by the parties as important and by the court as necessary to the first judgment’.Footnote ⁶⁷ Thus, while there may be variations among the different common law jurisdictions, the criterion is clearly normative and requires an assessment of what are the main grounds in the parties’ submissions and what are the rational bases that led the court to arrive at its decision.

By contrast, the civil law approach, at least from the outset, is a rather formalistic one that focuses on the operative part of a judgment for determining the scope of res judicata.Footnote ⁶⁸ However, in practice, the Romanic legal traditions appear to take a more generous approach, looking also at the ‘necessary underlying motivation’ of a judgment, whereas the Germanic traditions, notably in Germany and Switzerland, cling rather strictly to the principle that the dispositif circumscribes the scope of res judicata and only allows deviations where the ‘exact meaning and extent’ of the operative part ‘is not self-explanatory’.Footnote ⁶⁹ Hence, while the practice is not entirely consistent among civil law countries, the approach of at least the Germanic traditions resembles the focus on ‘inseparable’ reasons evident in several ICJ judgments.

The approach taken in twentieth century state-to-state arbitration appears to be more influenced by the common law approach. In the Pious Fund arbitration between the United States and Mexico, the very first dispute before the Permanent Court of Arbitration, decided in 1902, the tribunal held that the decision by the umpire of the US-Mexican Claims Commission constituted res judicata between the United States and Mexico. The tribunal adopted a very broad view as to the scope of res judicata:

Here, clearly the English common law tradition resounds. ‘[A]ll the parts of the judgment,’ i.e., the entire ratio decidendi forms part of the res judicata.

In the Channel arbitration between the United Kingdom and France over the delimitation of the continental shelf, the Court of Arbitration, seized by the United Kingdom to interpret its earlier decision of 30 June 1977, held in its decision of 14 March 1978 that:

According to this, the reasoning may be taken into account but only if it is linked to the dispositif. Therefore, this approach may be placed somewhere in the middle between the broad approach taken in Pious Fund and the narrow Germanic concept.Footnote ⁷² However, ‘a point not so settled in the dispositif’, by way of logic, must mean something different – and potentially broader – than a reasoning ‘inseparable from the dispositif’. In addition, the Court of Arbitration eventually arrived at a result that aligned with the broad scope of res judicata asserted by the United Kingdom, since the dispositif of the decision of 30 June 1977 consisted essentially of only a list of coordinates delimiting the continental shelf between the two parties and thus was not ‘self-standing’.Footnote ⁷³

2.2. In particular: The ICJ's case law with regard to res judicata

Outside of Article 60 proceedings, the case law of the Court on res judicata falls into two broad categories. In the first category are judgments and advisory opinions dealing with the res judicata effect of arbitral awards and similar decisions, whereas the second category comprises contentious cases (original judgments), where the Court had to judge on the res judicata effect of its own prior decisions.

As to the first category, the PCIJ adopted a narrow view of the scope of res judicata in its Advisory Opinion in Polish Postal Service in Danzig. The issue before the Court was whether the decision of the High Commissioner of the League of Nations, entrusted with deciding disputes between Poland and the Free City of Danzig under the Treaty of Versailles, had decided with binding force that the use of the Polish Postal service in Danzig was confined to Polish authorities and offices.Footnote ⁷⁴ It was undisputed among the parties that the operative part of the High Commissioner's decision did not contain such a finding. However, such a finding might arguably have been deduced from the motifs of the decision.Footnote ⁷⁵ The Court, taking note of the broad understanding endorsed in the Pious Fund arbitration, nonetheless determined that:

In the King of Spain and 1989 Arbitral Award cases, the Court noted that it could not re-examine the dispute before the arbitral tribunal, without pronouncing on the scope of res judicata.Footnote ⁷⁷

Turning to the second – and for the present purposes even more interesting – category of res judicata effect of prior judgments of the Court, in the aforementioned Haya de la Torre case of 13 June 1951 the ICJ held that here it was called upon to decide on the surrender of Mr. Haya de la Torre rather than on whether granting him diplomatic asylum was illegal, which was the matter before the Court in the Asylum case of 20 November 1950.Footnote ⁷⁸ Denying res judicata effect of the Asylum case was only the logical consequence of the Court's rejection, in the interpretation decision of 27 November 1950, of Columbia's application that the Court should interpret the Asylum judgment of 20 November 1950 as having decided also on Mr. Haya de la Torre's surrender.Footnote ⁷⁹

Very interesting is the comparison with the more recent judgment in the Genocide case of 26 February 2007.Footnote ⁸⁰ By ten votes to five, the Court found that it had already decided in its 1996 judgment on preliminary objections,Footnote ⁸¹ ‘by necessary implication’, that Serbia enjoyed standing before the Court. The issue of jurisdiction ratione personae under the ICJ Statute had only been addressed in the merits phase because Serbia had in the meantime dropped its claim – asserted at many occasions, however, at least not expressly before the Court in the preliminary objections phase – that it continued Yugoslavia's UN Membership and thereby the status as ipso facto party to the ICJ Statute.Footnote ⁸² Although the issue of party status to the Statute was not at all before the Court in the preliminary objections phase – instead, the claims submitted merely pertained to the validity of jurisdictional title arising from the Genocide ConventionFootnote ⁸³ – the majority of the judges held in 2007 that its 1996 judgment constituted res judicata also as to Serbia's standing under the Statute:

The Court went on to conclude that:

As noted by several commentators,Footnote ⁸⁶ the Court thus employed a very broad understanding of res judicata in the 2007 Genocide judgment. The Court in effect argued that because Serbia did not raise issues of standing in the preliminary objections phase Serbia was precluded from having the Court revisit the matter of jurisdiction, albeit the 1996 judgment only found that it had ‘jurisdiction to adjudication upon the dispute’ ‘on the basis of Article IX of the [Genocide Convention]’Footnote ⁸⁷. As Stephan Wittich observed, the Court's approach resembles the doctrine of ‘issue estoppel’ under English law.Footnote ⁸⁸ The ‘necessary implication’ and ‘logical construction’ the Court refers to pertains to the motifs rather than merely the dispositif, as evinces the reference to the reasoning of the 1996 judgment in paragraph 132 of the 2007 judgment.Footnote ⁸⁹

A tendency for a broader understanding of res judicata may also be found in the Court's judgment of 4 May 2011 on the application of Honduras to intervene in the Territorial and Maritime Dispute (Nicaragua v. Colombia).Footnote ⁹⁰ In this case, Honduras sought to intervene according to Article 62 of the ICJ Statute in a maritime dispute between Nicaragua and Colombia with regard to matters of maritime delimitation that formed the subject matter of a dispute between Honduras and Nicaragua and that had resulted in a judgment by the Court of 8 October 2007,Footnote ⁹¹ which had delimited the maritime frontier between the two latter states with regard to that dispute. The Court, in the 2011 judgment, declined Honduras’ application to intervene. It stated that the 2007 judgment constituted res judicata and that Honduras’ arguments raised in its application to intervene would lead it to reconsider the Court's reasoning provided in the 2007 judgment, ‘which was an essential step leading to the dispositive of that Judgment’.Footnote ⁹²

2.3. Conclusion: Broad or narrow concept?

A wide scope of res judicata, as employed in the Genocide or Territorial and Maritime Dispute cases as well as in the Pious Fund arbitration,Footnote ⁹³ appears at odds with the ICJ's reasoning in, e.g., Haya de la Torre. If, as the Court held in Genocide, the question of standing under the ICJ Statute is ‘necessarily implied’ in a pronouncement on the jurisdiction ratione materiae based on the Genocide Convention, why would the obligation to surrender Mr. Haya de la Torre not be ‘necessarily implied’ in a finding that granting him asylum was illegal? In both instances, the explicit finding is logically connected to the (allegedly) implicit one: the Court moving to the merits phase may be read as assuming that there is jurisdiction on all counts, including ratione personae; finding that Mr. Haya de la Torre must be surrendered may be read as assuming that he cannot enjoy asylum in Peru and that granting him such asylum was illegal. The difference between the two matters may be that the question of its jurisdiction is one the Court has to decide ex officio and thus regardless of the parties’ submissions, while the same is not true for the substantive matters relevant in the Asylum and Haya de la Torre cases.Footnote ⁹⁴ However, opacity remains as to the consistency of the case law of the Court and international tribunals with regard to the scope of res judicata.

The Court's astonishingly broad understanding of res judicata in a case where it had to decide on the binding effect of one of its own previous judgments, in contrast to, for example, the aforementioned Polish Postal Service in Danzig, King of Spain and 1989 Arbitral Award cases, is more easily explained when revisiting the rationale behind the res judicata effect in international law. If the ultimate goal is the avoidance of re-litigation of identical or similar disputes, legal security, and, eventually, the maintenance of peace by preserving the trust in the binding and final character of international legal dispute settlement, the scope of res judicata, when considered in subsequent but original judgments, must be broad. The more of the earlier judgment is regarded as final and binding, the less of the issue can be re-litigated and the more legal security promotes the international actors’ faith in international adjudication.

Also, in the 2011 judgment in Territorial and Maritime Dispute, while it is not entirely clear whether the Court's choice of the word ‘essential’ – as opposed to ‘inseparable’ – was deliberate with regard to the wider or narrower approach to the concept of res judicata, the same underlying rationale as in the 2007 Genocide judgment applies here too. In the 2011 judgment, the Court clearly sought to prevent Honduras from re-litigating a matter that had already been considered by the Court. The Court therefore found itself again in a situation where a narrow concept of res judicata could have undermined the authority of its prior judgments.Footnote ⁹⁵

Therefore, regarding implied motifs, for example, as res judicata, as the Court did in the Genocide case, remains true to the rationale behind the doctrine.

Taking the very same rationale as point of departure in an interpretation proceeding reveals what I may call the competing concepts of res judicata. We arrive at the opposite conclusion: In order to prevent re-litigation and to further legal security and faith in international adjudication, the object of interpretation must be narrow. The broader the understanding of what constitutes res judicata, the more of the original judgment can be considered again by the Court in an interpretation proceeding and thus the more what should be interpretation turns into reconsideration.Footnote ⁹⁶

To put it polemically, ideally, the Court would have to reduce res judicata to the dispositif when interpreting an original judgment pursuant to Article 60 of the ICJ Statute, while, when confronted with the question of res judicata of a previous decision in a proceeding under Article 36 of the Statute, it would have to stretch its scope to include all the motifs as well. This is perplexing. How can the Court, in fact any court or tribunal, entertain diametrical concepts for the same doctrine, depending on the proceedings chosen?

The need for a uniform concept is obvious, considering that the issue of res judicata may arise in consecutive proceedings, first under Article 60 and then under Article 36 of the ICJ Statute. In fact, this was the situation in the Asylum and Haya de la Torre cases, but a conflict did not arise because the Court chose a narrow concept of res judicata in both cases. However, based on its case law on Article 60 proceedings prior to the Temple case judgment of 11 November 2013, one may be sceptical about whether the Court, e.g., in the Genocide case would have employed the same broad concept of res judicata, if it had had to interpret its 1996 judgment and then subsequently had to decide on the same matter in a new proceeding under Article 36 of the Statute. In turn, contrasting Asylum/Haya de la Torre and Genocide (and the 2011 judgment in Territorial and Maritime Dispute or the Pious Fund arbitration), whether the applicant can actually bring a new case on a similar subject matter must not depend on whether it resorts first to Article 60 proceedings and only thereinafter to Article 36 proceedings – and then is successful with its application as in Asylum/Haya de la Torre – or seizes the Court directly with a new proceeding pursuant to Article 36 of the Statute – and then is unsuccessful with its application, if one follows the approach taken, e.g., in the Genocide or 2011 Territorial and Maritime Dispute cases.Footnote ⁹⁷

This brings us back to the Temple case. The Court, despite its reference to ‘essential’ reasons of the original judgment that may form part of the res judicata, and criticized by Judge Cançado Trindade in his separate opinion,Footnote ⁹⁸ eventually applied very rigorously its approach, taken in earlier case law,Footnote ⁹⁹ that merely the operative part and those parts of the reasoning that are ‘inseparable’ from the operative part are subject to res judicata effect. Despite revisiting the evidence before the Court in the original judgmentFootnote ¹⁰⁰ and its reasoning in such judgment pertaining to the geographical features of the territory in question as presented in the Annex I map,Footnote ¹⁰¹ the Court's interpretation of the original judgment was always premised on the operative part and remained within the confines of what it had pronounced therein.Footnote ¹⁰²

In sum, I think the Court should choose the narrow approach – i.e., only the dispositif and those parts of the motifs that are ‘inseparable’Footnote ¹⁰³ from the dispositif form part of the res judicata effect of a judgment by the Court – as the uniform concept of res judicata to be employed equally in both Article 36 and Article 60 proceedings. The Temple case is a very good example of how even such narrow understanding of res judicata, when skilfully applied, serves very well to illuminate what the Court decided in its original judgment. As just described, the Court was able to construe what it meant by ‘vicinity’ of the Temple by making reference to the evidence, the oral pleadings, and the geographical features of the Temple area as presented in the Annex I map before the Court in 1962. All this did not go beyond a construction of the dispositif and reasoning ‘inseparable’ from it, since all these formed part of the parties’ submissions and therefore of the very core of the elements of res judicata, in particular the petitum and the causa petendi.Footnote ¹⁰⁴

Furthermore, the Asylum and Haya de la Torre cases evince how the narrow concept operates in the relationship between Article 60 and Article 36 proceedings and in fact how such concept avoids a conflict between the two proceedings. The approach in Haya de la Torre was consistent with what the Court held in the Asylum interpretation judgment, i.e., that surrender was a ‘new’ issue, separate from the legality of the asylum. While both matters are logically connected, they are nonetheless distinct from one another. There is no evidence that the Court's decision to deny res judicata effect of the Asylum case and thus to allow new proceedings in Haya de la Torre has in any way undermined the authority of its decision or its role in international dispute settlement. However, by contrast, given the political and military tensions between Cambodia and Thailand between 2008 and 2011, it is submitted that a broad understanding of res judicata and, in turn, a reconsideration of the Court's reasoning in the Temple case would have had a rather devastating effect.

Finally, employing the narrow approach of res judicata also for consecutive original decisions has its roots in the PCIJ's jurisprudence, as the above reference to the Advisory Opinion in Polish Postal Service in Danzig demonstrates.Footnote ¹⁰⁵ The Court refused – however, in a rather indirect and polite manner – to embrace the broad view endorsed in the Pious Fund arbitration. Consequently, it declined to find that the High Commissioner's opinion expressed in the motifs of his decision formed part of what he had decided with binding force and limited the scope of res judicata in effect to the narrow approach later endorsed by the ICJ.

Therefore, the narrow approach serves well to reconcile the frictions currently existing in the case law of the Court and inter-state arbitration with regard to the competing concepts of res judicata I fleshed out in this contribution.