1  Despite the lack of the formal principle of stare decisis in international law, international courts and tribunals frequently refer to their own previous decisions. They also refer to decisions rendered by other international courts and tribunals when making their own decisions. The latter phenomenon is called cross-referencing. The present entry examines situations where cross-referencing occurs, its background, its asymmetrical nature, and its possible effects.

2  A brief explanation of what is meant by ‘other’ courts and tribunals for the purposes of the present entry is needed. The Permanent Court of International Justice (PCIJ) is not considered here as ‘another’ court to the International Court of Justice (ICJ), in view of their functional continuity (Shaw, 2016, I.13). In addition, the tribunal in inter-State arbitration A is not considered in this entry as ‘another’ tribunal to the tribunal in inter-State arbitration B, given the similarity of their functions. For similar reasons, the tribunal in an investment arbitration is not considered here as ‘another’ tribunal to the tribunal in another investment arbitration. Accordingly, the present entry does not examine cases where an inter-State arbitral tribunal refers to decisions rendered by another inter-State arbitral tribunal or an investment tribunal refers to decisions rendered by another investment tribunal. On the other hand, a reference by an investment tribunal to decisions made by an inter-State arbitration does fall within the scope of the present entry.

3  The present entry examines cross-referencing made between international courts and tribunals. Reference by an international court to a domestic court or vice versa is thus out of the scope of the present entry.

4  The concept of ‘cross-referencing’ is not identical to but a part of that of ‘judicial dialogue’ or ‘dialogue des juges’. The term ‘dialogue des juges’ was first used by Bruno Genevois in his conclusions as the commissaire du gouvernement at the Conseil d’Etat of France (Ministère de l’Intérieur c Cohn-Bendit, conclusions de M. Genevois, 1978, 168). Since its first use, the term ‘dialogue des juges’ or ‘judicial dialogue’ ‘presupposes a two-way or multi-way exchange’, while cross-referencing, which is the subject of the present entry, ‘may only be in one direction’ (Jones, 2014, 74).

5  Finally, the present entry adopts a large concept of ‘courts and tribunals’, which include dispute settlement organs, ie panels and the Appellate Body, of the World Trade Organization (‘WTO’), as well as human rights treaty organs.

6  Cross-referencing can be observed in a wide variety of situations. Most frequently, it occurs in relation to treaty interpretation as well as identification of customary international law rules and general principles of international procedural law.

7  International courts and tribunals frequently refer to decisions of other courts and tribunals dealing with the same treaty provisions.

8  The evident example of such treaty is the United Nations Convention on the Law of the Sea (‘UNCLOS’) (Ivanova, 2019, 157–64). Where applying the Convention’s relevant provisions, the ICJ (eg on Arts 3 and 15 UNCLOS, Territorial and Maritime Dispute, Nicaragua v Colombia, 2012, para 178; referring to Delimitation of the Maritime Boundary in the Bay of Bengal, Bangladesh/Myanmar, 2012, para 169; and Delimitation of the Exclusive Economic Zone and the Continental Shelf, Barbados/Trinidad and Tobago, 2006, para 238 (‘Barbados and Trinidad and Tobago’)), the International Tribunal for the Law of the Sea (‘ITLOS’) (eg on Arts 74 and 83 UNCLOS, Bangladesh/Myanmar, paras 225–39; referring to, inter alia, Maritime Delimitation in the Black Sea, Romania v Ukraine, 2009, para 116; and Delimitation of the Maritime Boundary, Guyana v Suriname, 2007, para 342) and arbitral tribunals (eg on the distinction between the delimitation of the continental shelf under Art 83 UNCLOS and the delineation of its outer limits under Art 76, Bay of Bengal Maritime Boundary Arbitration, Bangladesh v India, 2014, para 80; referring to Delimitation of the Maritime Boundary in the Bay of Bengal, Bangladesh/Myanmar, para 376; Territorial and Maritime Dispute, Nicaragua v Colombia, para 129) frequently refer to each other.

9  Human rights treaties are another example. The ICJ, when interpreting relevant provisions of the International Covenant on Civil and Political Rights (‘ICCPR’), refers to the ‘constant practice’ (Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, 2004, para 109 (on Art 2 ICCPR)) or the ‘jurisprudence’ or ‘interpretative case law’ (Ahmadou Sadio Diallo, Republic of Guinea v Democratic Republic of the Congo, 2010, para 66 (on Art 13 ICCPR)) of the Human Rights Committee (‘HRC’). Similarly, the ICJ refers to the ‘case law’ of the African Commission on Human and Peoples’ Rights (ACommHPR) when interpreting relevant provisions of the African Charter on Human and Peoples’ Rights (‘ACHPR’) (Ahmadou Sadio Diallo, Merits, para 67). The Appeals Chamber of the International Criminal Tribunal for Rwanda (‘ICTR’), which considers itself to be competent to apply the ICCPR, refers to the HRC’s jurisprudence when interpreting relevant provisions of the ICCPR (Barayagwiza v Prosecutor, 1999, paras 40, 63–64, 67). The African Court on Human and Peoples’ Rights (ACtHPR), whose jurisdiction extends to any human rights instruments ratified by the States concerned (Art 3 (1) Protocol to the African Charter on Human and Peoples’ Rights on the Establishment of an African Court on Human and Peoples’ Rights), refers to the jurisprudence of the HRC when interpreting the ICCPR (Konaté v Burkina Faso, 2014, paras 152–53, 161).

10  The Agreement on the European Economic Area has ‘the objective of establishing a dynamic and homogeneous European Economic Area (EEA), based on common rules and equal conditions of competition’ (Preamble Agreement on the European Economic Area) and aims ‘to promote … the respect of the same rules’ (Art 1 (1) EEA Agreement). In order to guarantee the homogeneity of the EEA, the provisions of the EEA Agreement, ‘in so far as they are identical in substance to corresponding rules of ’ the Treaty on European Union and the Treaty on the Functioning of the European Union and to EU legislative acts, ‘shall … be interpreted in conformity with the relevant rulings of the Court of Justice of the European [Union] given prior to the date of signature of [the EEA] Agreement’ (Art 6 EEA Agreement). The Court of Justice of the European Free Trade Association (EFTA Court) (Art 108 (2) EEA Agreement) is thus legally required to rely upon the pre-EEA Agreement jurisprudence of the Court of Justice of the European Union (‘CJEU’) (Magnússon, 2011, 513; European Union, Court of Justice and General Court).

11  European Union (‘EU’) legislative acts relating to the ‘four freedoms’ (see Art 1 (2) (a)–(d) EEA Agreement) adopted after the entry into force of the EEA Agreement are incorporated into the latter through amendment of its Annexes (Arts 98 and 102 EEA Agreement). When interpreting relevant Annexes of the EEA Agreement, the EFTA Court evidently refers to the jurisprudence of the CJEU. However, since rules applicable in the EEA are supposed to be ‘homogeneous’, the relationship between the two Courts are not one-way and the CJEU also refers to the jurisprudence of the EFTA Court (eg Opel Austria GmbH v Council of the European Union, 1997, para 108) (Speitler, 2017, 26; Baudenbacher, 2016, 187–90).

12  Similarly, Article 52 Charter of Fundamental Rights of the European Union (‘Charter’) provides that rights which correspond to those guaranteed by the Convention for the Protection of Human Rights and Fundamental Freedoms (‘European Convention on Human Rights’ or ‘ECHR’) shall have the same meaning and the scope as those laid down by the ECHR. The CJEU, considering that the relevant provisions of the Charter shall have the same meaning as the corresponding provisions of the ECHR ‘as interpreted by the caselaw of the European Court of Human Rights’ (McB v LE, 2010, para 53), often refers to the case law of the European Court of Human Rights (ECtHR) in order to interpret relevant provisions of the Charter (eg Land Baden-Württemberg v Panagiotis Tsakouridis, 2010, para 52) (Búrca, 2013, 174–76).

13  When interpreting applicable treaty provisions, international courts and tribunals often refer to decisions of other courts and tribunals interpreting and applying other rules of international law concerning similar issues, even where the treaty provisions do not envisage homogeneity with such other rules.

14  The Diallo judgment of the ICJ, when interpreting Article 13 ICCPR and Article 12 (4) ACHPR relating to the expulsion of non-nationals, ‘note[d]’ the jurisprudence of the ECtHR and the Inter-American Court of Human Rights (IACtHR) respectively on Article 1 Protocol 7 of the ECHR and Article 22 (6) American Convention on Human Rights (‘ACHR’), ‘the said provisions being close in substance to those of’ the ICCPR and the ACHPR (Ahmadou Sadio Diallo, 2010, para 68).

15  Human rights treaty organs frequently refer to each other (Turgis, 2012, 404–18). For example, in Sitaropoulos and Giakoumopoulos v Greece (2012), the ECtHR, in order to support its conclusion that Article 3 Protocol No 1 of the ECHR does not oblige States Parties to enable their nationals living abroad to exercise the right to vote, refers to the HRC’s General Comment on Article 25, Statehood Solidarity Committee v United States (2003) of the Inter-American Commission on Human Rights which refers to the jurisprudence of the HRC and the ECtHR, and Purohit and Moore v Gambia (2003) of the ACommHPR which refers to the abovementioned General Comment of the HRC (2012, at paras 26–31, 72). To give but a few more examples, the HRC, in its views in Larrañaga v Philippines (2006), cites őcalan v Turkey (2005) of the ECtHR to support its conclusion that the imposition of the death sentence after the conclusion of proceedings which did not meet the due process requirements amounts to inhuman treatment in violation of Art 7 ICCPR (2006, at para 7.11, fn 59). The IACtHR, in considering that the ACHR must be interpreted ‘in the context of the evolution of the fundamental rights of the human person in contemporary international law’ (Advisory Opinion OC 16-99, 1999, para 115), refers to the jurisprudence of the ECtHR, the HRC, the Committee on Economic, Social and Cultural Rights (CESCR), the Committee on the Rights of the Child (CRC), the United Nations Committee against Torture (‘CAT’), and the Committee on the Elimination of Discrimination Against Women (CEDAW) to arrive at the conclusion that sexual orientation is one of the prohibited categories for discrimination under Art 1 (1) ACHR (Riffo and Daughters v Chile, 2012, paras 85–89). The ACtHPR also refers to the jurisprudence of the ECtHR and the IACtHR to ‘repris[e] the decriminalizing approach to press offenses’ (Oré, 2020, 45) when interpreting Article 9 African Charter on the freedom of expression (Konaté v Burkina Faso, paras 158–59).

16  Tribunals established under regional trade agreements often refer to World Trade Organization (‘WTO’) (World Trade Organization, Dispute Settlement) jurisprudence when interpreting relevant provisions of the applicable agreement (Zang, 2020, 114–24). For example, an arbitral panel established under Chapter 20 North American Free Trade Agreement (‘NAFTA’) states that ‘the Panel carefully examined the way in which the ‘like product’ concept had been defined in prior GATT/WTO decisions’ in attempting to perform an analysis of ‘like product’ under the NAFTA (US Safeguard Action Taken on Broom Corn Brooms from Mexico, Final Report, 1998, para 66; see also Bovine Carcasses and Half Carcasses, Fresh or Chilled Originating in the United States of America (Dumping), 2004, paras 11.51–11.54; Binational Panel Review: North American Free Trade Agreements (NAFTA and USMCA)).

17  Investment tribunals also refer to WTO jurisprudence when interpreting relevant provisions of the applicable investment treaty (Kurtz, 2016). For example, the Continental tribunal refers to the WTO jurisprudence on general exceptions ‘[s]ince the text of Art. XI [of the Argentina-US BIT on the security exception] derives from the parallel model clause of the U.S. FCN treaties and these treaties in turn reflect the formulation of Art. XX of GATT 1947’ (Continental Casualty Company v Argentina, 2008, paras 192–95; Arbitration: International Centre for Settlement of Investment Disputes (ICSID)). Similarly, investment tribunals refer to WTO jurisprudence when interpreting provisions on national treatment (Pope & Talbot Inc v Canada, 2001, paras 45–63, 68–72) or procurement (Mesa Power Group LLC v Canada, 2016, para 436; Permanent Court of Arbitration (PCA)).

18  Conversely, the WTO Appellate Body (Appellate Body: Dispute Settlement System of the World Trade Organization (WTO)) or panels rarely refer to investment tribunals, probably because investment tribunals do not deal with issues that are frequently put forward before them. A rare example is a panel report referring to investment tribunals when examining the concept of ‘even-handedness’ in relation to Article XX (g) General Agreement on Tariffs and Trade (‘GATT’), which the panel considers shares common elements with the fair and equitable treatment, which is frequently discussed in investment tribunals (China – Rare earths, Panel Report, 2014, paras 7.319–7.322).

19  Articles II and III Convention on the Prevention and Punishment of the Crime of Genocide (‘Genocide Convention’) ‘are reproduced in’ Article 4 Statute of the International Criminal Tribunal for the Former Yugoslavia (ICTY) (Report of the Secretary-General Pursuant to Paragraph 2 of Security Council Resolution 808 (1993), para 46) and in Article 2 Statute of the International Criminal Tribunal for Rwanda (ICTR). The identity of the wording explains the ICJ’s reference to the jurisprudence of the ICTY and the ICTR in cases where the ICJ interprets and applies the Genocide Convention (Application of the Convention on the Prevention and Punishment of the Crime of Genocide, Bosnia and Herzegovina v Serbia and Montenegro, 2007, paras 188, 190, 195, 197–201, 300; Application of the Convention on the Prevention and Punishment of the Crime of Genocide, Croatia v Serbia, 2015, paras 129, 142, 148, 157–8, 161). The judgments of the ICJ are referred to by the ICTY in turn (Prosecutor v Vujadin Popović et al., 2015, para 439; Prosecutor v Zdravko Tolimir, 2015, para 226). For the same reasons, the ECtHR also refers to the ICTY jurisprudence when examining the interpretation of Article II Genocide Convention (Vasiliauskas v Lithuania, 2015, para 176).

20  The International Criminal Court (ICC) frequently refers to the jurisprudence of ad hoc international criminal tribunals when interpreting the Rome Statute of the ICC (‘Rome Statute’), the Elements of Crimes, or the Rules of Procedure and Evidence of the ICC. For example, the Trial Chamber relied on the jurisprudence of the ICTY to elucidate the concepts of ‘armed conflict’ and ‘international armed conflict’, which are mentioned but not explicitly defined in the Rome Statute (Art 8 (2) (b) and (e). Prosecutor v Lubanga, Judgment pursuant to Article 74 of the Statute, 2012, paras 531–32, 541–42) and the Appeals Chamber referred to the jurisprudence of the ICTY to support its findings on the nexus requirement in the Elements of Crimes (Art 8 (2) (b) and (e); Prosecutor v Ntaganda, 2017, para 68). Reference to the jurisprudence of ad hoc international criminal tribunals is also made in relation to provisions on the disclosure of the identity of Prosecution witnesses (Rule 81 (4); Prosecutor v Lubanga, Decision on Second Defence Motion for Leave to Appeal, 2006, 10, fn 32, referring to the ICTR) and on the standard of review on appeal (Arts 81–83 Rome Statute; Prosecutor v Lubanga, 2014, para 46, referring to the ICTY, the ICTR, and the Special Court for Sierra Leone (SCSL)) (Appeals Chamber: International Criminal Courts and Tribunals).

21  On the other hand, the ICC refers to but refuses to follow the ICTY jurisprudence where it finds that the text of the Rome Statute does not allow it to do so. Such examples include the ICTY jurisprudence on ‘joint criminal enterprise’ in relation to Article 25 Rome Statute (Procureur v Lubanga, 2007, paras 329–41).

22  International courts and tribunals frequently refer to decisions of other courts and tribunals when identifying applicable rules of customary international law.

23  An evident example is customary rules of treaty interpretation. To identify ‘customary rules of interpretation of public international law’ (Art 3 (2) Dispute Settlement Understanding (‘DSU’)), the WTO Appellate Body refers to the jurisprudence of the ICJ, the ECtHR, and the IACtHR (US - Gasoline, Appellate Body Report, 1996, 17, fn 34; 23, fn 45). To confirm that the rules contained in Articles 31 to 33 Vienna Convention on the Law of Treaties (‘VCLT’) reflect customary international law, the International Tribunal for the Law of the Sea (ITLOS) refers to the ICJ, the Guinea and Guinea-Bissau arbitration (1985, at para 41) and the WTO Appellate Body (Responsibilities and Obligations of States with Respect to Activities in the Area, 2011, 28, para 57). To give a more specific example, an ICSID tribunal (Orascom TMT Investments SARL v Algeria, 2017, paras 287–88, fns 304–6) refers to the PCIJ/ICJ, the WTO Appellate Body and an inter-State arbitration (Iron Rhine, Belgium/Netherlands, 2005, para 49) to justify the application of the principle of effet utile.

24  Examples of cross-referencing made for identification of customary international law rules are too numerous to be exhaustively mentioned here. It is useful, however, to point out that cross-referencing regarding customary rules often evolves like a snowball. Such an example is found regarding customary international law rules on maritime delimitation. The Chamber of the ICJ in Gulf of Maine stated that resource-related considerations might be taken into account in maritime delimitation only if such delimitation was ‘likely to entail catastrophic repercussions for the livelihood and economic well-being of the population of the countries concerned’ (Delimitation of the Maritime Boundary in the Gulf of Maine Area, Canada/United States of America, 1984, para 237). This statement was referred to with approval by the arbitral tribunal in Barbados and Trinidad and Tobago (at para 241). The ICJ then referred to the relevant part of the Barbados and Trinidad and Tobago award (Maritime Delimitation in the Black Sea, para 198). This back-and-forth cross-referencing was then referred to by the ITLOS (Delimitation of the Maritime Boundary in the Atlantic Ocean, Ghana/Côte d’Ivoire, 2017, para 452).

25  Cross-referencing is also frequent when international courts and tribunals interpret and apply general principles of international procedural law.

26  An example is la compétence de la compétence (Competence-Competence). The power of international courts and tribunals to decide on their own jurisdiction or la compétence de la compétence is considered to be ‘part, and indeed a major part, of the incidental or inherent jurisdiction of any judicial or arbitral tribunal’ by the ICTY (Prosecutor v Tadić, 1995, para 18), referring to the jurisprudence of the ICJ, although the ICTY Statute contains no provision explicitly providing for the power, unlike the Statute of the ICJ (‘ICJ Statute’) (Art 36 (6) ICJ Statute). The Arbitration Commission established in the Conference for Peace in Yugoslavia similarly relied on the jurisprudence of the ICJ to confirm its compétence de la compétence in the absence of an explicit provision granting such power to it (Commission d’arbitrage, 1993, 586, para 3). The WTO Appellate Body did the same (US - 1916 Act, Appellate Body Report, 2000, para 54, fn 30). More extensive cross-referencing was made by the ICC in a decision concerning the alleged deportation of members of the Rohingya people, in which Pre-Trial Chamber I stated that la compétence de la compétence ‘has been recognized by numerous international courts and tribunals’, referring to the PCIJ/ICJ, the IACtHR, the WTO Appellate Body, investment tribunals, and international criminal tribunals (Decision on the Prosecution’s Request for a Ruling on Jurisdiction under Article 19(3) of the Statute, 2018, paras 30–31).

27  As the last example shows, cross-referencing concerning general principles of international procedural law tends to be wide-ranging, supposedly because the procedural rules applicable to international courts and tribunals are rather rudimentary. In Thailand – Cigarettes, the panel of the WTO refers to the jurisprudence of the ICC, the ICTR, investor-State arbitration, and investor-international organization arbitration on the issue of lawyer-client privilege (2018, paras 7.37–7.40, fns 171–80), explaining that ‘[g]iven that the relevant WTO dispute settlement rules and procedures are silent on the issue of lawyer-client privilege, we consider that it is appropriate to review wider international practice in this regard’ (at para 7.35) (Attorney-Client Privilege).

28  Cross-referencing in this field is of course used to introduce procedural practice adopted by other international courts and tribunals. In this respect, the evolution of cross-referencing regarding the binding force of provisional measures is worth mentioning here. Following the ICJ judgment in LaGrand that recognized the binding force of provisional measures indicated pursuant to the ICJ Statute, whose text is ambiguous on this point (LaGrand, Germany v United States of America, 2001, para 109; Provisional Measures: International Court of Justice (ICJ)), the ECtHR in Mamatkulov also found that its provisional measures were binding, referring to the LaGrand judgment, despite the similarly ambiguous language of the relevant provisions of the ECHR (Mamatkulov and Askarov v Turkey, 2005, paras 117, 128; Provisional Measures: European Court of Human Rights (ECtHR)). Later, an ICSID tribunal stated, referring to LaGrand and Mamatkulov, that ‘it is now generally accepted that provisional measures are tantamount to orders, and are binding’ and found that those ‘recommended’ pursuant to Article 47 Convention on the Settlement of Investment Disputes between States and Nationals of Other States were also binding ‘[i]rrespective of the precise terminology used’ (Perenco Ecuador Limited v Republic of Ecuador, 2009, paras 66, 69–70, 74; Provisional Measures: Investment Arbitration).

29  It is to be noted, however, that cross-referencing is not always made to introduce procedural practice adopted elsewhere. In Lubanga, the ICC Trial Chamber, after confirming that the ICC Statute and Rules did not expressly provide for the possibility of parties preparing witnesses for testimony, looked to the practice of the ICTY and the ICTR, as the prosecution argued that the ICC should follow their well-established practice of witness proofing. The Trial Chamber, however, refused to do so. It declared that it was not persuaded that the application of the practice adopted by these ad hoc tribunals was appropriate as regards the preparation of witnesses for trial, since ‘the [Rome] Statute move[d] away from procedural regime of the ad hoc tribunals, introducing additional and novel elements to aid the process of establishing the truth’ (Prosecutor v Lubanga, Decision Regarding the Practices Used to Prepare and Familiarise Witnesses for Giving Testimony at Trial, 2007, para 45).

30  Cross-referencing is rarely an obligation for international courts and tribunals, although there are a few notable exceptions. The SCSL Statute provides that ‘[t]he judges of the Appeals Chamber of the Special Court shall be guided by the decisions of the Appeals Chamber of the International Tribunals for the former Yugoslavia and for Rwanda’ (Art 20 (3) Statute of the SCSL). The EFTA Court is required to follow the pre-EEA CJEU jurisprudence (see para 10 above). The EU has concluded several Free Trade or Association Agreements that require panels to be established under them to ‘adopt an interpretation which is consistent with any relevant interpretation established in rulings of the WTO Dispute Settlement Body’ (Art 14.16 EU-Republic of Korea Free Trade Agreement, 2010; Art 320 EU-Ukraine Association Agreement, 2014; Art 322 (2) EU-Central America Association Agreement, 2012).

31  Some international courts and tribunals are statutorily encouraged, though not formally obliged, to practice cross-referencing (see the EFTA Court as regards the post-EEA jurisprudence of the CJEU, paras 10–11 above; the CJEU as regards the ECtHR, para 12 above; and the ICC as regards human rights treaty organs, para 52 below. See also Art 60 African Charter on Human and Peoples’ Rights). The most prominent example is Article 38 (1) (d) ICJ Statute. Although it is often argued that the provision obliges the ICJ to practice cross-referencing (Andenas and Leiss, 2017, 936–37), it is generally considered to ‘encourage’ the ICJ to do so (Pellet and Müller, 2019, 946).

32  However, cross-referencing is widely practiced by international courts and tribunals that do not have such statutory basis. For example, the ICC Trial Chamber in Lubanga considered the jurisprudence of the SCSL ‘[a]lthough the decisions of other international courts and tribunals are not part of the directly applicable law under Article 21 of the [Rome] Statute’ (Prosecutor v Lubanga, Judgment pursuant to Article 74 of the Statute, para 603). The ITLOS refers to Article 38 (1) (d) ICJ Statute to emphasize the relevance of decisions of other international courts and tribunals, despite the fact that its Statute is silent on this point (Art 23 ITLOS Statute. See also Art 293 UNCLOS; Delimitation of the maritime boundary in the Bay of Bengal, Bangladesh/Myanmar, para 184). The ICTY Trial Chamber in Kupreškić goes further when it states that Article 38 (1) (d) ICJ Statute ‘must be regarded as declaratory of customary international law’ (Prosecutor v Kupreškić, 2000, para 540).

33  Even in the absence of a clear legal basis, cross-referencing seems to be encouraged and facilitated by human relationships, though it is difficult to empirically validate the relevance or estimate the degree of the relevance of such human elements. For example, when the ICTR was established, it was intended to ‘ensure a unity of legal approach’ with the ICTY, which was already in existence (Report of the Secretary-General Pursuant to Paragraph 5 of Security Council Resolution 955 (1994), para 9). Article 13 (3) Statute of the ICTR thus provides that two of the judges elected in accordance with the ICTR Statute shall be members of the Appeals Chamber of the ICTY (see also Art 14 (4) Statute of the ICTY). It is therefore not surprising at all to see a large number of decisions and judgments rendered by the two ad hoc international criminal tribunals refer to each other.

34  The relevance of human elements is also pointed out with respect to the ICC. It is said that the influence of the jurisprudence of the ICTY and the ICTR over the ICC is partly explained by the fact that many of the people who have been recruited by the ICC had previously worked at the ad hoc tribunals (Bitti, 2015, 428).

35  It is also to be noted that many of the members of UNCLOS Annex VII tribunals are incumbent or former ITLOS judges (Annex VII Arbitration: United Nations Convention on the Law of the Sea (UNCLOS)) and that it is frequent to see incumbent or former ICJ judges in investment tribunals. It should be noted that in 2020 the ICJ published a compilation of decisions concerning the external activities of its members, according to which ‘Members of the Court may only participate in inter-State arbitration cases’. It is telling that Gilbert Guillaume, former President of the ICJ, presided over the tribunal in Mobil, in which the tribunal conducted a detailed analysis of the ICJ jurisprudence on the rules applicable to the interpretation of unilateral acts (Mobil Corporation Venezuela Holdings BV and others v Venezuela, 2010, paras 84–95).

36  In addition, more informal exchanges between judges and arbitrators may encourage cross-referencing. Juliane Kokott, Advocate General of the CJEU, notes:

judges may meet their counterparts from other jurisdictions at conferences, anniversaries or during official visits paid by the members of one institution to those of another. They may also publish articles in law journals or discuss certain issues of mutual interest within specialized networks uniting their various judicial institutions. All these occasions can give rise to highly fruitful exchanges on issues of practical relevance to Europe’s common legal order (Kokott and Dittert, 2014, 44).

37  This observation was made in the European context but applies more widely. According to the then President Higgins, the ICJ hosted seminars on legal topics of mutual interest, in which judges of other international courts and tribunals participated (2009, at 411). She also explains that the ICJ ‘set up a system whereby summaries and/or relevant excerpts of cases that address legal questions of particular interest are exchanged with judges from other international courts and tribunals’ (at 411). The importance of such informal exchanges was also emphasized by the then President Paik of the ITLOS (Paik, 2019, 8). More systematically, the ACtHPR, the ECtHR, and the IACtHR published the Joint Law Report 2019, in which each court explains the developments in their respective jurisprudence. The Report states:

38  Last but not least, international courts and tribunals are often invited to refer to each other by disputing parties. In Territorial and Maritime Dispute, Colombia and Nicaragua agreed that the applicable law in that case was ‘customary international law reflected in the case law of [the ICJ], the [ITLOS] and international arbitral courts and tribunals’ (at para 114). It is common that disputing parties invoke and rely on the jurisprudence of other international courts and tribunals before the court or the tribunal where they are defending their cases.

39  It is often said that there is certain asymmetry in the practice of cross-referencing. The ICJ is thus often criticized for its ‘narcissisme jurisprudentiel’ (Kamto, 2003, 415; see also Mendelson, 1996, 83): it is frequently referred to by other courts and tribunals but it rarely refers to the others. This criticism seems prima facie well-founded when one compares the number of cross-references made by the ICJ and the other international courts and tribunals. For example, the ICJ has referred to the ITLOS in four cases while the latter referred to the former in 13 cases as of September 2021. However, we need to look at the practice more closely, particularly because the ‘narcissism’ criticism mentioned above was made in the late 1990s and the early 2000s; in other words, before or shortly after the international community experienced an explosive increase in the number of international courts and tribunals. Already in 2006, the then President Higgins of the ICJ emphasized the importance of ‘read[ing] each other’s judgments’ (2006, at 804).

40  In order to be referred to by other courts and tribunals, the ‘target’ court must have already made a decision dealing with a question that the referring court or tribunal is working on. This simple logical requirement explains quite a few situations.

41  The PCIJ frequently referred to arbitral decisions since they were the only available international precedents when the first permanent international court in history was created. For example, when enunciating the well-known ‘Chorzów principle’, which would be referred to and relied on by various courts and tribunals countless times, the PCIJ stated that the principle ‘seems to be established by international practice and in particular by the decisions of arbitral tribunals’ (Factory at Chorzów, 1928, 47). Similarly, the ICJ often refers to inter-State arbitration dealing with similar issues. For example, in its first maritime delimitation case after the 1977 Anglo-French maritime delimitation arbitration (Delimitation of the Continental Shelf between the United Kingdom and France, United Kingdom v France, 1977), the ICJ did not hesitate to refer to the arbitral decision (Continental Shelf, Tunisia/Libya, 1982, paras 66, 99; Judicial Precedent).

42  As regards the asymmetry in cross-referencing between the ICJ and the ITLOS mentioned above, it has to be recalled that the ITLOS started to function in 1996 and dealt primarily with requests for prompt release in its first years. Since no other court or tribunal than the ITLOS has ever dealt with requests for prompt release (see Art 292 (1) UNCLOS), there is no wonder that ITLOS judgments on prompt release were not referred to by other courts or tribunals, including the ICJ.

43  It was in 2012 that the ICJ first referred to the ITLOS precedent, when asked to determine the amount of compensation (Ahmadou Sadio Diallo, Compensation, 2012, para 56). The ITLOS had already had a chance to deal with the questions relating to the quantum in 1999 (M/V‘SAIGA’ (No. 2), Saint Vincent and Grenadines v Guinea, 1999, paras 167–76) and Diallo was the first case after the establishment of the ITLOS in which the ICJ dealt with such questions. In other words, the ICJ referred to the ITLOS jurisprudence as soon as it faced questions that had already been dealt with by the latter. This open attitude, which is far from ‘narcissistic’, was illustrated again in the same year, when the ICJ referred to the very first maritime delimitation judgment of the ITLOS (Delimitation of the maritime boundary in the Bay of Bengal, Bangladesh/Myanmar) immediately after it was rendered (Territorial and Maritime Dispute, Nicaragua v Colombia, paras 114, 178; see also Maritime Delimitation in the Caribbean Sea and the Pacific Ocean and Land Boundary in the Northern Part of Isla Portillos, Costa Rica v Nicaragua, 2018, para 153).

44  Cross-referencing between the ICJ and international criminal tribunals shows a similar evolution pattern. In the first years of their activities, the ICTY and the ICTR often referred to the jurisprudence of the ICJ on issues relating to general international law (Barayagwiza v Prosecutor, para 46, fn 127 (ut res magis valeat quam pereat); Prosecutor v Strugar, 2005, para 227, fn 775 (customary status of the Hague Regulations); Prosecutor v Halilović, 2005, para 25 (Common Article 3 Geneva Conventions as a common ‘core’ of fundamental humanitarian standards); Prosecutor v Galić, 2006, para 87, n 271 (principle of distinction)), while the latter did not refer to the former. However, when the ICJ was seized with a case which contained matters that had already been dealt with by international criminal courts, the ICJ referred to them (see above para 19).

45  With respect to human rights courts and treaty organs, it has already been mentioned that the ICJ often refers to human rights courts and treaty organs (see above para 9). The first case in which the ICJ had an occasion to interpret provisions of human rights treaties was Legality of the Threat or Use of Nuclear Weapons. In its Advisory Opinion, in which the interpretation of Article 6 ICCPR was discussed, the Court did not mention the HRC (1996, at para 25). However, it has to be remembered that the HRC had not yet articulated its position on the interpretation of Article 6 at that time. When the ICJ was seized with a case concerning provisions of human rights treaties on which relevant treaty organs had expressed their positions, it did not hesitate to refer to them (Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, see above para 9). The ICJ also referred to human rights courts and treaty organs in Diallo concerning principles governing compensation, particularly in respect of injury resulting from unlawful detention and expulsion. These issues had already been discussed by such human rights courts and treaty organs but it was the first time for the ICJ to deal with them (Ahmadou Sadio Diallo, Compensation, paras 13, 24, 33, 40, 49, 56).

46  A similar phenomenon is observed in cross-referencing between the CJEU and the EFTA Court. When the EFTA Court started to function in 1994, the then Court of Justice of the European Communities (‘CJEC’) had already developed rich jurisprudence, which constituted part of acquis communautaire. Therefore, the EFTA Court basically followed the CJEC jurisprudence, while the latter did not refer to the former, in the early years of the EFTA Court. However, when the EFTA Court rendered a judgment on questions that had not been dealt with by the CJEC (Paranova v Merck, 2003), the latter followed the former (Boehringer Ingelheim and Others, Judgment, 2007, para 38). There is now said to be a relationship of a ‘symbiotic nature’ between the two courts (Skouris, 2014, 12; Baudenbacher, 1996, 193).

47  Between courts and tribunals of regional integration organizations, it is pointed out that although the Permanent Review Court and ad hoc arbitral tribunals of MERCOSUR (MERCOSUR Dispute Settlement System), the Caribbean Court of Justice (CCJ) as well as the Court of Justice of the Andean Community of Nations (Andean Community of Nations, Court of Justice) frequently, though selectively, refer to the jurisprudence of the CJEU (Wojcikiewicz Almeida, 2018, 243–49; Alter and Helfer, 2017, 44–45; 90–110; Caserta, 2020, 153–76), their referencing remains ‘unilateral’ (for MERCOSUR, see Wojcikiewicz Almeida, 2015, 400–2). This asymmetrical relationship may be explained, at least partially, by the fact that the CJEU predates the others. The CJEU does not have to look to their South American counterparts since it has already established rich jurisprudence.

48  It is reasonable to suppose that international courts and tribunals are tempted to look at what others are doing when they are faced with a question that they have never dealt with (for the WTO, see Hoeffner, 2012, 143). It follows that the wider the scope of the jurisdiction of the court or tribunal is, the more likely that its jurisprudence is referred to by the others, because a court or tribunal with a wider scope of jurisdiction is likely to deal with a case that has not been dealt with by other courts or tribunals with a narrower scope of jurisdiction. This ‘partage de compétence informel’ (Ruiz Fabri and Gradoni, 2016, 203) partly explains why the ICJ is frequently referred to by other courts and tribunals but does not usually refer to the others on questions of general international law. Such examples include treaty interpretation rules (US - Gasoline, Appellate Body Report, 17, fn 34; 23, fn 45; Iron Rhine, Belgium/Netherlands, para 45), rules on the interpretation of unilateral acts (Mobil Corporation Venezuela Holdings BV and others v Venezuela, paras 84–95); the conditions for acquiescence or tacit agreement (‘Hoshinmaru’, 2007, para 87; Delimitation of the Maritime Boundary in the Bay of Bengal, Bangladesh/Myanmar, para 117; Delimitation of the Maritime Boundary in the Atlantic Ocean, Ghana/Côte d’Ivoire, paras 212, 215, 226), estoppel (Delimitation of the Maritime Boundary in the Bay of Bengal, Bangladesh/Myanmar, para 124; M/V ‘Norstar’, Panama v Italy, 2016, para 306; Chagos Marine Protected Area, Mauritius v United Kingdom, 2015, paras 435–37), the non-binding character of resolutions of the General Assembly of the United Nations (Delimitation of the maritime boundary in the Indian Ocean, Mauritius/Maldives, 2021, para 224; Coastal State Rights in the Black Sea, Ukraine v Russian Federation, 2020, para 172), the legal status of the precautionary principle (EC - Hormones, Appellate Body Report, 1998, para 124, fn 93), due diligence obligation (Request for Advisory Opinion submitted by the Sub-Regional Fisheries Commission, 2015, para 131), customary status of the obligation to conduct environmental impact assessment (Responsibilities and obligations of States with respect to activities in the Area, paras 147–48), the conditions for the state of necessity (M/V ‘SAIGA’ (No. 2), Saint Vincent and the Grenadines v Guinea, para 133; CC/Devas (Mauritius) Limited and others v India, 2016, para 219; EDF International SA and others v Argentina, 2016, para 335), and piercing the corporate veil (Tokios Tokelės v Ukraine, 2004, para 54; Gambrinus v Venezuela, 2015, para 142).

49  Conversely, if a court or tribunal’s jurisdiction is limited to a certain specific field, for example, law of the sea, trade, investment, crimes, etc, it is less likely that such courts and tribunals with limited jurisdiction are referred to by the others. For example, as of September 2021 the ICJ has never referred to the jurisprudence of the WTO. This is probably because questions usually discussed before the Appellate Body or panels have not been submitted to the ICJ after the establishment of the WTO (see Elettronica Sicula, United States of America v Italy, 1989, para 111 on national treatment and most-favoured-nation treatment). Similarly, no precedent of investment arbitration has been mentioned by the ICJ (Pellet, 2013, 225; Dimetto, 2019, 786). In cases where disputing parties referred to investment arbitration cases, the ICJ simply abstained from mentioning them (Seizure and Detention of Certain Documents and Data, Timor-Leste v Australia, 2014, 147; Immunities and Criminal Proceedings, Equatorial Guinea v France, 2018, 292) or stated that the issues before it were different from those discussed in investment arbitration (Ahmadou Sadio Diallo, Preliminary objections, 2007, paras 88–9; Obligation to Negotiate Access to the Pacific Ocean, Bolivia v Chile, 2018, para 162).

50  In this respect, human rights courts and treaty organs constitute exceptions. Although human rights courts and treaty organs principally deal with issues relating to human rights, it is remarkable that other international courts and tribunals frequently refer to them even in cases where they apply non-human rights norms of international law (for cross-referencing in the application of human rights treaties, see above para 15), to the extent that it is argued that the ‘contents and core values [of human rights law] today are of major importance for the interpretation of international law as a whole’ (Weiß and Thouvenin, 2015, viii).

51  For example, the ICJ referred to the ECtHR when interpreting and applying rules on State immunity (Jurisdictional Immunities of the State, Germany v Italy: Greece intervening, 2012, paras 72–73. In turn this ICJ judgment was referred to by the ECtHR in Stichting Mothers of Srebrenica and Others v the Netherlands, 2013, para 158). The ECtHR was also referred to by an inter-State arbitral tribunal on non-material damage for wrongful detention (Arctic Sunrise Arbitration, Netherlands v Russian Federation, 2017, paras 80–81).

52  However, it is international criminal tribunals (Galand, 2019, 87; Lobba and Mariniello, 2017) and investment tribunals (Kube and Petersmann, 2018, 228–53) that most frequently refer to human rights courts and treaty organs.

53  Although the Appeals Chamber makes it clear that ‘the Court was not established to be an international court of human rights’ (Prosecutor v Saif Al-Islam Gaddafi and Abdullah Al-Senussi, 2014, para 219), the ICC frequently refers to the jurisprudence of the HRC, the IACtHR, and the ECtHR (eg Prosecutor v Lubanga, 2008, paras 46–47; Prosecutor v Katanga and Chui, 2008, paras 32, fn 39; 39, fn 42). This practice has a statutory basis, as Article 21 (3) Rome Statute provides that the application and interpretation of law by the ICC ‘must be consistent with internationally recognized human rights’.

54  More interesting examples are the ICTY and the ICTR, whose statutes do not contain a provision similar to Article 21 (3) Rome Statute. The ICTR in Barayagwiza referred to the jurisprudence of the HRC on the ground that the ICCPR ‘is part of general international law’ and to that of the ECtHR and the IACtHR ‘as evidence of international custom’ (at para 40). Similarly, the ICTY in Limaj found that ICTY rules on provisional release must be ‘read in the light of the ICCPR and the ECHR and the relevant jurisprudence’ because ‘[t]hese human rights instruments form part of public international law’ (Prosecutor v Limaj and others, 2003, paras 10, 12).

55  In investor-State arbitration, arguments based on human rights are raised both by investor-claimant and the host State-respondent for multiple purposes (Baetens, 2019, 230–48). Although an investment tribunal ‘is not a human right court’ (Yukos Universal Limited v Russian Federation, 2014, para 765), a number of investment tribunals refer to human rights courts and treaty organs on substantive issues such as the constitutive elements of expropriation (SAUR International c Argentine, 2012, para 445, fn 430) the margin of appreciation (OperaFund Eco-Invest SICAV plc and Schwab Holding AG v Spain, 2019, para 552, fn 1104), the proportionality analysis of regulatory measures (Técnicas Medioambientales Tecmed, SA v Mexico, 2003, para 122), the obligation to ensure the right to fair trial as part of fair and equitable treatment (Toto Costruzioni Generali SpA v Lebanon, 2009, para 160), the (non-)self-judging character of security exceptions (El Paso Energy International Company v Argentine, 2011, para 598), the availability of moral damages (Bernhard von Pezold and others v Zimbabwe, 2015, para 910, fn 95), as well as procedural questions such as the obligation for tribunals to give reasons for their decisions (Tulip Real Estate and Development Netherlands BV v Turkey, 2015, para 152). The ECtHR is by far the most favourite target, probably because Protocol (No 1) of the ECHR is the only internationally legally binding instrument that provides for the property rights of legal persons. However, though less frequently, investment tribunals do refer to the IACtHR (Bernhard von Pezold and others v Zimbabwe, para 910, fn 95), and the HRC (Toto Costruzioni Generali SpA v Lebanon, para 160).

56  On the other hand, human rights courts and treaty organs only rarely refer to the jurisprudence of international criminal courts or investment arbitration. It is pointed out that ‘the matters on which international criminal jurisprudence could be of use to the Strasbourg Court surface only in a small share of its cases’ (Vasiliev, 2015, 377. For such rare examples, see Vasiliauskas v Lithuania; Jorgic v Germany, 2007, para 69). This observation applies to other human rights courts and treaty organs as well as their rare reference to investment arbitration.

57  In a case in which the legal status of the Chagos Archipelago was discussed, the ITLOS Chamber stated, in relation to the ICJ’s Advisory Opinion on the Chagos Archipelago (Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, 2019, 95), that ‘judicial determinations made in advisory opinions carry no less weight and authority than those in judgments because they are made with the same rigour and scrutiny by the “principal judicial organ” of the United Nations with competence in matters of international law’ (Delimitation of the maritime boundary in the Indian Ocean, Mauritius/Maldives, para 203). Although international courts and tribunals generally do not mention the ICJ’s status as the principal judicial organ of the United Nations, it may be the case—though difficult to empirically prove—that they rely on the ICJ’s authority as the principal judicial organ of the United Nations when they refer to its jurisprudence.

58  The attitude of the ICTY is quite interesting in this respect. As discussed below, its Appeals Chamber in Tadić explicitly parts company with the ICJ concerning the attribution of conducts. In a later case, the appellants criticized the Tadić judgment for not following the ICJ’s precedent. The Appeals Chamber responded: ‘although the ICJ is the “principal judicial organ” within the United Nations system to which the Tribunal belongs, there is no hierarchical relationship between the two courts. Although the Appeals Chamber will necessarily take into consideration other decisions of international courts, it may, after careful consideration, come to a different conclusion’ (Prosecutor v Delalić and others, 2001, para 24 [footnote omitted]). However, as discussed below (see below para 66), the ICTY ended up by accepting the distinction made by the ICJ.

59  It is argued that the ICJ reasserts its position at the centre of the international legal system through its own practice of cross-referencing (Andenas and Bjorge, 2015, 33; Andenas, 2015, 539, 566–69). It may indeed be desirable that the ICJ has a prominent role to achieve the coherent development of international law. However, such a role could only be earned ‘through recognition of and deference to its intrinsic authority and the quality of its legal reasoning and findings’ (Abi-Saab, 1999, 929). The evolution of the ICTY’s attitude seem to represent such recognition. The ICJ will also have to ‘remain attractive’ so that States give it sufficient opportunities to develop its jurisprudence (Bodeau-Livinec and Giorgetti, 2016, 188–89).

60  It is said that international courts and tribunals practice cross-referencing to ‘make possible a decision which, in one form or another, will be as informed as possible; will have as high a quality as possible; will be as objective, fair and wise as possible; and will come about as efficiently as possible’ (Villiger, 2011, 197). As mentioned above (para 30), international courts and tribunals are rarely obliged to refer to decisions of others. They nevertheless do so ‘at their own initiative’, ‘to manage the inherent plurality of the fabric of international dispute settlement’ (Boisson de Chazournes, 2017, 72).

61  Cross-referencing is expected to be useful for courts and tribunals to render informed and objective decisions because it helps them to avoid interpreting and applying relevant international law rules in ‘clinical isolation from public international law’ (US - Gasoline, Appellate Body Report, para 17; Phoenix Action Ltd v Czech Republic, 2009, para 77). In other words, it helps international courts and tribunals to ensure and promote the integrity and coherence of international law (Webb, 2013, 220-8; Guillaume, 2010, 703).

62  Soon after the ITLOS rendered its first judgment on maritime delimitation, which extensively referred to the jurisprudence of the ICJ and arbitral tribunals dealing with the same issues (Delimitation of the maritime boundary in the Bay of Bengal, see above para 8), Yanai, the then president of the ITLOS, declared:

63  This statement suggests that international courts and tribunals consider that cross-referencing helps to enhance their legitimacy (Hoeffner, 2012, 147; Legitimacy of International Adjudication).

64  International courts and tribunals’ pursuit of coherence is particularly noticeable in their efforts to distinguish their cases when they arrive at conclusions seemingly different from those reached by others to justify theirs. They explain that critical factual elements are different (Delimitation of the Maritime Boundary in the Atlantic Ocean, Ghana/Côte d’Ivoire, para 285; Mobil Investments Canada v Canada, 2018, para 210) or that the difference in the applicable rules leads to a different conclusion (Prosecutor v Lubanga, Decision Regarding the Practices Used to Prepare and Familiarise Witnesses for Giving Testimony at Trial, para 45).

65  The efforts of international courts and tribunals to achieve coherence in the application of international law are well represented in the well-known conflicts between the ICJ and the ICTY concerning the rules of attribution. In Tadić, the ICTY Appellate Chamber, in dealing with the question of when, in an armed conflict which was prima facie internal, armed forces might be regarded as acting on behalf of a foreign power, thereby rendering the conflict international, considered that the notion of control found in general international rules on State responsibility was relevant. It then examined the ‘effective control’ test adopted by the ICJ in Nicaragua and found it ‘unconvincing’, considering that the text would not seem to be consonant with the logic of the law of State responsibility. According to the Appeals Chamber, the ‘overall control’ test was appropriate (Prosecutor v Tadić, 1999, paras 98, 115–20). A subsequent judgment of the Appeals Chamber clearly stated that it did not have to adhere to the ICJ jurisprudence (Prosecutor v Delalić and others; see above para 58).

66  The ICJ had an occasion to respond to the ICTY when it faced a question of whether genocide committed by certain groups in Bosnia Herzegovina was attributable to Serbia. The Court did not fail to clearly manifest its disagreement with the ICTY, stating that the argument in favour of the ‘overall control’ test, which ‘has the major drawback of broadening the scope of State responsibility well beyond the fundamental principle governing the law of international responsibility’, was ‘unpersuasive’ under the law of State responsibility (Application of the Convention on the Prevention and Punishment of the Crime of Genocide, Bosnia and Herzegovina v Serbia and Montenegro, paras 404, 406). However, it took pains to avoid criticizing the Tadić judgment itself. The Court admitted that ‘[i]n so far as the “overall control” test is employed to determine whether or not an armed conflict is international, which was the sole question which the Appeals Chamber was called upon to decide, it may well be that the test is applicable and suitable’ (Application of the Convention on the Prevention and Punishment of the Crime of Genocide, Bosnia and Herzegovina v Serbia and Montenegro, para 404). The ICJ thus attempted to distinguish its jurisprudence on State responsibility from the ICTY’s Tadić judgment on the internationalization of armed conflicts.

67  It seems that the distinction proposed by the ICJ was accepted by the ICTY. In Prlić, in which the accused pointed to the 2007 ICJ judgment to criticize the ICTY’s jurisprudence on ‘overall control’, the Appeals Chamber simply noted, without criticizing the 2007 ICJ judgment, that the ICJ had refrained from taking a position on the ‘overall control’ text in the context of the Tadić case (Prosecutor v Prlić, 2017, para 238). The ICC adopted the same approach, applying the ‘overall control’ test to the internationalization of armed conflicts without mentioning the relevance of the rules on the attribution of conducts under the law of State responsibility (Prosecutor v Lubanga, Décision sur la confirmation des charges, para 210; Prosecutor v Bemba, 2016, para 655. The latter judgment was reversed by the Appeals Chamber for reasons unrelated to the present entry).

68  Distinction is not always possible and international courts and tribunals often do not hesitate to refer to the jurisprudence of other courts and tribunals to clearly manifest their disagreement. The ECtHR thus disagreed with the Committee against Torture, which ‘has advocated [a plaidé]’ the position that Article 14 Convention against Torture on redress and compensation obliges State Parties to refrain from granting the alleged author of torture immunities from jurisdiction (Naït-Liman v Switzerland, 2018, para 189. For the position of the Committee against Torture, see General Comment No 3 (2012), para 38). More recently, the ICJ, while confirming that it should ‘ascribe great weight’ to the interpretation of human rights treaties adopted by the treaty organs, roundly and explicitly rejected the interpretation of Article 1 (1) International Convention on the Elimination of All Forms of Racial Discrimination adopted by the Committee on the Elimination of Racial Discrimination (CERD) that the term ‘national origin’ encompassed current nationality (Application of the International Convention on the Elimination of All Forms of Racial Discrimination, Qatar v United Arab Emirates, 2021, paras 100–1, 105. For the position of the Committee on the Elimination of Racial Discrimination, see Decision on the admissibility of the inter-State communication submitted by Qatar against the United Arab Emirates, 2019, paras 55–63). Although referencing between inter-State arbitral tribunals does not fall within this entry’s scope, it may be useful here to point out that the award on jurisdiction and admissibility of the South China Sea tribunal referred to the Southern Bluefin Tuna award (Australia and New Zealand v Japan, 2000, para 57) to declare that the latter’s interpretation of Article 281 UNCLOS was ‘not in line with the intended meaning of Article 281’ (South China Sea Arbitration, Philippines v China, 2015, para 223).

69  These frontal collisions are not necessarily detrimental to the coherence of international law. As already predicted by Jonathan Charney in 1998, when the judicialization of international law had just started:

The lack of a strictly hierarchical system allows international tribunals the opportunity to collectively contribute ideas to international law and facilitates the evaluation of those ideas by the international community as a whole. In the end, one would hope that the best norms would be widely adopted (1998, at 347).

70  In the present entry, we have examined cases where international courts and tribunals refer to decisions of other international courts and tribunals. However, there are cases where international courts and tribunals seem to take into account decisions of other international courts and tribunals, without expressly referring to them (Romano, 2009, 783). They often note that disputing parties, or third parties qualified to submit their opinions in the proceedings, referred to decisions of other international courts and tribunals but do not do so by themselves (Timurtaş v Turkey, 2000, para 80, noting a third party’s reference to the jurisprudence of the IACtHR; see also Voeten, 2010, 549). It also happens that minority opinions exhibit cross-referencing, while the majority opinion does not (Whaling in the Antarctic, Australia v Japan: New Zealand intervening, Judgment (Dissenting Opinion of Judge Owada), 2014, para 33, referring to the jurisprudence of the WTO Appellate Body).

71  In such cases, the attitude of the court or the tribunal in question may be understood in several ways. It may have found decisions of other international courts and tribunals were relevant and useful but considered it more prudent not to refer to them (Hennebel, 2007, 50–51, considering that the HRC in Sarma v Sri Lanka, 2003, implicitly relied on the IACtHR jurisprudence). Or it may have found them distinguishable or simply irrelevant. The causes and effects of such non-reference remain to be examined.

Shotaro Hamamoto