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  • Muskaan Garg

Identification v. Assertion of Law by the ICJ: A Tripartite Case Analysis

I. Introduction

In pursuit of peaceful dispute resolution between States, one of the long-standing solutions espoused has been the International Court of Justice’s (ICJ) adjudication in the realm of international law. Customary International Law (CIL) is enshrined underArticle 38(1)(b) of the ICJ Statute which empowers the ICJ to apply international custom as ‘evidence of a general practice accepted as law.’ ICJ is bound to abide by this application of international custom and cannot disregard the vital role of general practice (seeNicaragua v. United States of America). Its elusiveness has led to several attempts by the ICJ to define CIL and explore its facets within international law.

In ICJ’s interpretation of Article 38, its function is to ‘decide’ and ‘bring an end to the disputes before it’ (seeBosnia and Herzegovina v. Serbia and Montenegro).Article 59 of the ICJ Statute further highlights ICJ’s subsidiary role by declaring its judgments to be non-binding except between the parties and in respect of that case. However, this is all good in theory. Over the years, the uncertainty attached with CIL has legitimised ICJ’s unprecedented degree of influence over its determination. As a result, scholars like Pellet have expressed concern towards the dwindling legitimacy of CIL when ICJ ‘asserts’ its existence instead of ‘proving’ it.[1] Advancing Cassese’s observation of absence of a central law-making body having compulsory jurisdiction in the international legal system[2], it is argued that in exercise of ICJ’s authority in identifying the customary rules and defining their scope and content, it has accidentally or perhaps deliberately gone beyond its judicial role into the realm of law creation. This piece seeks to evaluate this contention through the analysis of three ICJ decisions,Fisheries (United Kingdom v. Norway) (1951) case, Legality of the Threat or Use of Nuclear Weapons Advisory Opinion (1996)andLegal Consequences of the Separation of the Chagos Archipelago from Mauritius Advisory Opinion (2019). It is argued that ICJ asserts law at its own convenience and is moving away from a strict application of the requirements of state practice and opinio juris as laid down in North Sea Continental Shelf Cases (Germany v. Denmark and the Netherlands).

II. Case analysis

A.Anglo-Norwegian-Fisheries-Case (1951)

The ICJ sided with Norway’s position that the method of delimitation of fisheries zone under the Royal Norwegian Decree of July 12, 1935, was not in contravention of international law. To support its conclusions, the Court relied on a general practice among several states which follow Norway’s straight-base lines method along with a lack of a state practice confirming the 10-mile rule to be an existing rule under CIL. Since it was an early day judgement, there was no reference made to opinio juris. To reach a conclusion, ICJ introduced the persistent objector rule suggesting that where a state acts contrary to an established customary practice and other states concede, it is to be treated as not bound by that original rule.[3] In applying this rule to Norway’s situation, the ICJ in true essence ‘recognised’ the existence of CIL. However, Cassese[4] and Thirlway[5] criticise this rule since it lacks the support of existing state practice. It is argued that by exempting Norway from following the CIL, the ICJ inched towards creating an exceptional rule under CIL. This attempt did manifest law creation tendencies. However, it has not been pleaded for many times since Fisheries and theAsylum (Colombia v. Peru) caseas now there is awidespread agreement that the persistent objector rule only applies when a CIL rule is emerging. Therefore, it appears-that-scholars-and-jurists-have-forgiven-ICJ’s-attempt to create CIL since international law was in its nascent stages.

The majority judge, Judge Alvarez, in hisindividual opinion expressly pointed towards the creation of general principles under Article 38 when the same cannot be formed from customs and conventions. That is, “if no principles exist for covering a given question, they must be created to conform to those conditions.” Although, the judgement largely demonstrates an interpretation of CIL, Judge Alvarez’s proposition indicates a possibility of a positive construction of CIL by the Court. It is contentious to approve of this proposition as any CIL rule that the ICJ invents using this understanding would be a legal fiction at best as the Court would not have perceived it but rather assumed it. However, according to Shaw, the situation of non-liquet as anticipated by Judge Alvarez where no applicable law is found is a rarity and general principles are almost always present for closing this gap.[6] Nonetheless, creation of new rules every time the Court is unable to answer a question would undermine the aim of international law – integration of community interests.

B.Nuclear-Weapons-Advisory-Opinion (1996)

The ICJ concluded that no CIL or conventional law universally prohibits the threat of use of nuclear weapons,but they can be used in case of armed conflict. On reading in fine print, it appears as if there was some opinio juris regarding illegality of threat or use of nuclear weapons but certainly no corresponding state practice. However, the ICJ found none. To reach this conclusion, the Court examined the presence of an opinio juris through analysis of the General Assembly (GA) resolutions. However, in Court’s opinion, the nature of consent under the relevant resolutions still fell short of establishing the existence of an opinio juris on illegality of use of such weapons. To this end, it is contended that the Court seems to place their trust in the GA resolution to come up with an opinio juris. Some have even gone to the extent to argue that in trying to find a source of CIL in GA resolutions, ICJ uses the shield of opinio juris to often create custom.[7]

This challenge has been ongoing sinceNicaragua v. United States of Americawherein the Court similarly referred to the attitude of states towards some GA resolutions which enabled it to extract an opinio juris. However, in the Nuclear Weapons AO, the ICJ seems to have adopted a restrictive approach as it acknowledges-that-resolutions-do-not-make-law-by-themselves-and focused on their normative value in providing evidence for establishing an opinio juris. Although the Court acknowledged the non-binding nature of the resolutions, it failed to provide any other instance or source to establish opinio juris in the matter. The very nature of CIL is dependent on behavioural patterns i.e., customs andnot on whether they are legal as is their impression under resolutions. A heavy reliance on GA resolutions is problematic as the United Nations is ultimately a political entity whereby the-reasons-to-support-or-oppose-a-stance-at-GA usually have underlying political motivations which can at no cost transpire into judicial pronouncements as the basis of a decision.[8] The use of such consensus may be beneficial in reaching a further nuanced opinio juris but cannot be the basis of it. Therefore, voting for a resolution cannot be held as conclusive evidence for opinio juris.

While-ICJ-may-seem-to-reconsider-its-position-under the Nicaragua judgement, the wording of the Nuclear Weapons A.O. still suggests ICJ’s reliance on resolutions to grant itself power to create custom. In response to the contention that answering a question posed by the GA would require the ICJ to legislate because of absence of a relevant rule in corpus juris, the Court reiterated its task to not only state the existing law but also hinted on expanding its scope and note its general trend in application of the law. Thus, ICJ also seems to normalise the assertion of custom under the garb of application of law. Scholars believe that CIL is moving away from the bottom-up approach of relying on state practice as in the case of Nicaragua to a top-down model of proclaiming the law rather than deducing it.[9] Hence, ICJ seems to depart from the traditional sense of custom and prefer this approach.

C.Chagos-Island-Advisory-Opinion (2019)

The Court had to ascertain if self-determination was a CIL rule when Mauritius acceded to independence in 1968. A timeline had to be determined for the crystallization of self-determination as a CIL rule. Here the Court again relied on a series of GA resolutions by ascribing it a normative value to only ‘assert’ that self-determination was already a CIL rule at that time. Marko Milanovic is preciselywary of this assertion as neither state practice nor opinio juris was established to reach the conclusion. Milanovic further made a remark that, “[it is] just good plain assertion, as the Court is so often wont [one's customary behaviour] to do.” Thereby, supporting the contention that the Court is often accustomed to assert CIL rules rather than proving them.

On-the-subject-of-normative-character-of-resolutions,-the-Court relied on the Nuclear Weapons A.O. to maintain that with regards to the right to self-determination as a CIL norm, the impugned resolution 1514 (XV) has a declaratory character, despite it only being a formal recommendation. In the Court’s view the normative character of the resolution is evident from its wording that, “[a]ll peoples have the right to self-determination”. On comparing the application of the normative value of resolutions in both Chagos A.O. and Nuclear Weapons A.O., it seems it is up to the Court to ascertain the weight attached to the consensus under a resolution. For instance, in Nuclear Weapons A.O. since some states had abstentions to GA resolutions declaring the use of nuclear weapons to be in direct violation of the UN Charter and that the use should be prohibited in certain formulations, the Court saw this as a clear sign of deep concern but still held that these resolutions fell short of establishing an opinio juris on the illegality of nuclear weapons. However, in case of Chagos A.O. also some states had abstentions, but the Court on trusting the wording of the resolution decided to assume its normative character as sufficient to establish state consent.

In so far as the application of the law by ICJ is concerned, although the Court claims that it reserves discretion in the application of a CIL rule, the Court often uses this discretion to emphasis importance of certain rules and interest. For example, inparagraph 180 of Chagos A.O., the Court suggests that there exists a binding obligation on all states to cooperate with the UN in completing Mauritius’ decolonisation since self-determination is an obligation erga omnes. Here, the Court seems to use the shield of erga omnes to elevate the existing right to self-determination to the higher level of peremptory norms. According toEggett and Thin such an elevation often renders the legal meaning of a CIL rule completely obscure. Therefore, the Court-in-defining-the-scope-of-a-rule-sometimes-oversteps-its-customary-basis-and-invents- something-else-which-might-lead-to-unintended-repercussions.

III. Final evaluation and the road ahead

From North Sea Continental Shelf cases (1969) to Chagos A.O. (2019) through Nicaragua (1986) and Nuclear Weapons A.O. (1996), the Court seems to have inconsistently used its own recipe for identifying CIL, i.e., the twin requirement of opinio juris and state practice. From deriving-opinio-juris-as-a-psychological-element-requiring-higher-standard of proof than showing continuous practice as evidence to deriving its evidentiary value from GA resolutions in Nicaragua and Chagos is a big leap. Moreover, in Chagos no state practice was also relied upon as against one in Fisheries. Therefore, if even after 70 years this inconsistency persists-it-is-safe-to modestly conclude-that-ICJ-asserts-law-at-convenience-on-a-case-to-case basis. Precisely, like in Nuclear Weapons A.O., a sense of convenient behaviour is witnessed in ICJ’s indecisiveness to admit a blanket prohibition of nuclear weapons. Despite referring to multiple treaties on human rights affirming the illegality of nuclear weapons and emphasising indispensability of humanitarian principles, the Court was conveniently unable to find an opinio juris on illegality amongst the states. Moreover, the Court very conveniently relied on the nuclear weapon-possessing states themselves regarding its non-proliferation where the very survival of a State would be at stake (seeparagraph 62). The Court specifically observed that the Security Council had no objections to nuclear weapon states making treaty reservation which allowed them to use nuclear weapons in certain circumstances.

Further, from the limited analysis in this paper, it is observed that ICJ in finding CIL is keener to rely on GA resolutions in advisory opinions, like in both Nuclear Weapons and Chagos. Reasons-for-it-may-be-rooted-in-the-liberty-that-comes-with-operating in an advisory capacity vis-à-vis while in a judicial capacity of solving disputes between two parties with higher burden.[10] Some even argue that ICJ often reviews and evaluate the resolutions of the political organs through its advisory jurisdiction.[11] Therefore, there might be a hint of politics involved in placing reliance on resolutions. Afterall, they are part of one ecosystem, the UN.

Keeping the political malafides debate aside, it is contended that the very nature of CIL is to be blamed for ICJ’s behaviour of accidently creating custom than merely determining it. Jörg Kammerhofer underlines a paradox that, “norms are created in part by acts which are precisely an application of the resultant norm.” [12] The underlying notion is that the act which makes the law is the act to which the law is applied. In the application of the norm, ICJ often tends to sidestep the consideration of all the acts which had led to the formation of that norm. The circling paradox makes it difficult for the Court to separate the assertion and application of the law by using the acts. Ultimately, under CIL, the subject’s behavioural patterns should matter.

The continuing trend of extracting opinio juris from resolutions and asserting CIL without valid legal basis will not only compromise CIL’s legitimacy but also ICJ’s own judicial character.[13] In the realm of CIL, irrespective of the non-binding nature of ICJ’s judgements, they are viewed as pronouncements underlining the patterns of conduct that have to be complied with. Therefore, ICJ cannot act independently and its actions are always at the mercy of state preferences since it operates in a state-centric system.[14] Thus, it can be argued that ICJ derives its effectiveness from States’ willingness to accede to its judgements. ICJ’s legitimacy-is-at-stake-when-it-disregards-state-practice-as-then it-seems to be operating without the participation of the States through state consent. Eventually, States will opt-out of ICJ’s jurisdiction, leaving it further powerless.

IV. Conclusion

Spanning over seventy years, the cases provide a panoramic view of the CIL landscape evoking ICJ’s indispensable influence over CIL. The inconsistency in the basis of ICJ decisions solidifies the belief that ICJ asserts custom at its own convenience and that its interpretation is overly flexible. Whether-it-is-the-adoption-of-the-persistent-objector-rule in the Fisheries case to break the deadlock or reference to GA resolutions for extracting opinio juris. ICJ’s behaviour uncovers its ability to create new rules and that CIL will always have a possibility of being created. Judicial activism must be restricted to unique or otherwise non-liquet situations. Like Judge Alvarez, scholars still maintain that law assertion can occur in circumstances where existing principles fail to provide an answer. However, further research is still solicited. At the end of the day, ICJ’s interpretation must not reduce custom to a fiction and retain its sanctity - in the spirit of international law and comity.

[1]A. Pellet, 'Shaping The Future Of International Law: The Role Of The World Court In Law Making', Looking to the Future: Essays on International Law in Honor of W. Michael Reisman (Martinus Nijhoff Publishers 2011)

[2] A. Cassese, International Law (OUP, 2005) 194-5

[3] Malcolm Shaw, International Law (7th edn, Cambridge University Press 2014) 67

[4] A. Cassese, International Law (New York: Oxford University Press 2005)

[5] Hugh Thirlway, ‘The Sources of International Law’ International Law by Malcolm D. Evans (New York: OUP, 2010) 95-121 <>

[6]Shaw (n 3)

[7] Loretta Chan, ‘The Dominance of the International Court of Justice in the Creation of Customary International Law’ (2016) 6 Southampton Student Law Review 44 <>

[8]Rosalyn Higgins, ‘The Development of International Law By The Political Organs Of The United Nations’ (1965) 59 Proceedings of the American Society of International Law at Its Annual Meeting (1921-1969)

[9] B. Simma and A. L. Paulus, ‘The Responsibility of Individuals for Human Rights Abuses in Internal

Conflicts: A Positivist View’ (1999) 93 AJIL 302, 307

[10] Mark Angehr, 'The International Court of Justice's Advisory Jurisdiction and the Review of Security Council and General Assembly Resolutions' (2009) 103 Nw U L Rev 1007


[12]Jörg Kammerhofer, ‘Uncertainty in the Formal Sources of International Law: Customary International Law and Some of Its Problems’ (2004) 15 (3) EJIL < >

[13]W. Michael Reisman, ‘Judge Shigeru Oda: A Tribute to an International Treasure’ (2003) 16 Lei-den J. Int’l L. 57, 63

[14] T. Ginsburg, ‘Bounded Discretion in International Judicial Law Making’(2004) 45 Va. J. Int'l L.


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