Guatemala’s Successful Application for Intervention and the Ongoing Debate between Article 59’s Importance and Irrelevance in Assessing Article 62 Intervention Requests

By Grace Miner, New York University School of Law, J.D., Class of 2027

Introduction

At the end of March 2026, the International Court of Justice (ICJ) announced that it is permitting Guatemala to intervene in the ongoing case between Belize and Honduras under Article 62 of the Court’s Statute, marking only the fourth time that the Court has allowed such an intervention. Per Article 85 of the ICJ’s Rules, this means that Guatemala will be allowed to submit a written statement to the Court and submit written observations during the case’s oral proceedings on matters related to the subject of its intervention: the question of sovereignty over the Sapodilla Cayes in the Gulf of Honduras and fishing rights in the surrounding waters. 

The judges unanimously agreed that Guatemala adequately demonstrated it possesses an “interest of a legal nature” in the sovereignty dispute over the Sapodilla Cayes that “may be affected” by the Court’s decision. However, a separate opinion from Judge Hilary Charlesworth reveals that the Court notably steered clear of fully engaging in an ongoing debate about the relevance of applying Article 59 of the ICJ Statute when analyzing Article 62 intervention requests. Article 59, which sets out that “the decision of the Court has no binding force except between the parties and in respect of that particular case,” has previously been relied upon by the Court when assessing whether a third State’s potential legal interests will be affected such that Article 62 intervention is permissible. The Court has permitted intervention at times where it believes its decision will have binding effects on the requesting third party despite the protection afforded by Article 59, but it has refused to do so where it finds that the requesting party will face no binding effects, eliciting notable dissents from individual judges. 

This blog post will first consider what the Court has previously said about the relationship between Articles 62 and 59 through its decisions and individual judges’ dissenting opinions before turning to its most recent comments in accepting Guatemala’s application last month. Ultimately, the Court’s recent decision is a step forward in clarifying the relationship between the Articles, but more work remains for the Court to fully elaborate on its reasoning and respond to the longstanding critique that Article 59 should have no place in Article 62 intervention consideration. 

Article 62 and its Contentious Relationship with Article 59

Article 62 of the ICJ Statute states:

“l. Should a state consider that it has an interest of a legal nature which may be affected by the decision in the case, it may submit a request to the Court to be permitted to intervene.

2. It shall be for the Court to decide upon this request.”

Unlike Article 63 interventions, whereby every State that is a party to a treaty being interpreted by the Court has the right to intervene, a State must apply to intervene under Article 62 and “demonstrate convincingly” that it possesses a “legal interest” that “may be affected” by the Court’s final decision and/or reasoning. While Paragraph (2) declares that the Court may exercise discretion in responding to States’ Article 62 intervention requests, the Court has clarified that this discretion only extends to determining whether the intervening State has met the obligations set out under Paragraph (1) and cannot be a matter of policy choice. 

In previous judgments on Article 62 intervention requests, the Court has established that a sufficient legal interest “has to be the object of a real and concrete claim of that State, based on law, as opposed to a claim of a purely political, economic or strategic nature.” It has also found that a general interest in how the Court will apply international law rules and principles to a particular case does not rise to the level of a legal interest for Article 62 purposes. When determining whether a State’s asserted legal interest may be affected, the Court has been clear that this requirement constitutes a lower standard than “will or must be affected.” 

The Court has inconsistently invoked Article 59 of the ICJ Statute (“the decision of the Court has no binding force except between the parties and in respect of that particular case”) when assessing whether the “may be affected” requirement is met. While some of the Court’s judgments on Article 62 have not engaged with Article 59 at all, two prominent judgments explicitly consider whether the Court’s decisions in the relevant case will have binding impacts on the intervening third State to determine whether that State’s legal interest may be affected. In denying Costa Rica’s application for intervention in Territorial and Maritime Dispute (Nicaragua v. Columbia), the Court stated that in order to successfully intervene, a State must show that its legal interest “needs a protection that is not provided by the relative effect of decisions of the Court under Article 59 of the Statute.” Here, the Court felt it could adequately draw the requested boundary line between Nicaragua and Colombia without having to interfere with Costa Rica’s recognized legal interests in the region, and thus any decision in the case would have no precedential effects on Costa Rica. This meant that Article 59 was adequately protective of Costa Rica’s legal interests, leaving Costa Rica unable to meet the “may be affected” requirement for Article 62 intervention. Twelve years earlier, in the Land and Maritime Boundary (Cameroon v. Nigeria), the Court instead permitted Equatorial Guinea’s application to intervene precisely because it found Article 59 protection to be insufficient: the Court acknowledged that it would “eventually run into maritime zones where the rights and interests of Cameroon and Nigeria will overlap those of third States,” meaning it could not cleanly draw boundaries without having a binding impact on Equatorial Guinea. 

These applications of the relationship between Articles 62 and 59 were met with skepticism from individual judges. In his dissenting opinion from the Court’s judgement rejecting Costa Rica’s application to intervene in Territorial and Maritime Dispute, Judge Awn Shawkat Al-Khasawneh argued that “Article 59 cannot substitute for protection under Article 62” since “the protection … afforded by Article 59 … is of a different nature and operates in a different manner.” He noted that “protection under Article 59, in the sense of shielding a non‑intervening third party from the effects of res judicata, and protection under Article 62, designed to give a would‑be intervener a chance to be heard in order to protect an interest before the merits, are entirely different provisions in their purpose and scope.” Also dissenting from the Court’s intervention decision in Territorial and Maritime Dispute, Judges Antônio Augusto Cançado Trindade and Abdulqawi Ahmed Yusuf agreed that Article 59 does not have a “direct bearing” on Article 62 and cited to Judge Sir Robert Jennings’ earlier critique of Article 59’s application in Italy’s application to intervene in Continental Shelf (Libyan Arab Jamahiriya/Malta). In his dissent, Judge Jennings emphasized that applying Article 59 to find that a third State’s legal interests will not be affected simply because that State would not be formally bound by the Court’s final decision would mean all third States not party to disputes would be unable to demonstrate a legal interest that may be affected as required by Article 62. According to Judge Jennings, “to interpret one article of the Statute in such a way as to deprive another article in the same section of the Statute of al1 meaning, cannot be right.”

The Court’s Application of Article 59 in Assessing Guatemala’s Application 

While only Honduras formally objected to Guatemala’s application, both Honduras and Belize called into question Guatemala’s claim that its asserted legal interests may be affected by pointing to the protective power of Article 59 and the fact that the Court’s decision in their dispute would technically not bind Guatemala. In response to the States’ invocation of Article 59, the Court expressed its concerns with the limits of applying Article 59 similar to the argument put forth by Justice Jennings, stating “to hold that Article 59 shields a third State from the effect of a decision in a case to which it is not a party would eliminate the need for interventions altogether, thus rendering Article 62 superfluous.” Despite this acknowledgment, it went on to apply an analysis of Article 59 when comparing the present case to both Territorial and Maritime Dispute and Land and Maritime Boundary. Analogizing Guatemala’s position to that of Equatorial Guinea in Land and Maritime Boundary, the Court found that it could not rule on who between Belize and Honduras was sovereign over the Sapodilla Cayes without having binding implications on Guatemala, who likewise asserted sovereignty rights. In this way, the Court found that Article 59 protection was insufficient, requiring it to permit Guatemala to intervene just as it had permitted Equatorial Guinea to intervene in Land and Maritime Boundary. 

In her separate opinion, Judge Charlesworth took issue with the Court’s choice to once more invoke Article 59, particularly its overly general position that “in the view of the Court, Article 59 does not necessarily insulate third States from the effects of any decision which the Court may render.” According to Judge Charlesworth, “the use of the word ‘necessarily’ implies that there may be instances where Article 59 could serve as sufficient protection for potential interveners,” which would be a “categorical mistake” given her agreement with Judge Al-Khasawneh that the two Articles do not overlap and thus an analysis of Article 59 should not feature in any judgements on Article 62 intervention requests. 

Conclusion

The Judgment’s extended discussion of Article 59 suggests that the Court knows it must weigh in on the ongoing debate surrounding whether Article 59 is important or irrelevant in assessing Article 62 intervention applications. But by applying the same Article 59 analysis it has used previously to determine that Guatemala possesses a legal interest that may be affected, the Court has missed an opportunity to fully clarify the relationship between the two Articles moving forward. As Judge Charlesworth highlighted in her dissent, the Court does well to acknowledge that Article 59 does not always prevent a third State from facing the impact of a dispute between two parties, as these are the circumstances for which third party intervention was created. But to suggest that there are circumstances in which Article 59 protection is sufficient, meaning intervention should be rejected, without providing a more detailed explanation of the interplay between the two Articles or a formal acknowledgement of prominent critiques leaves third States in the dark as they hope to use intervention as an important vehicle for protecting their legal interests in contentious cases. At a time when intervention is being pursued at a higher frequency than ever, such guidance on both Article 62 and Article 63 intervention requirements is critical.