The jus cogens Nature of the Prohibition of Genocide in Sudan v. UAE: A New Case, the Same Old Omission

[Luciano Pezzano is Professor of Human Rights at the University of Business and Social Sciences (UCES, Argentina) and Lecturer of Public International Law at the National University of Cordoba (UNC, Argentina)]

On 5 March 2025, the Republic of Sudan instituted proceedings before the International Court of Justice (ICJ) against the United Arab Emirates (UAE), for breaches of the Genocide Convention. The case presents a great number of issues for legal analysis, from the value of the UAE’s reservation to Article IX of the Convention, to the issues of attribution of responsibility (and the known ICJ’s position on the effective control test), as well the notorious fact that the victims of the alleged genocide –the Masalit people– are also the same victims (with the Fur and the Zaghawa) of the alleged genocide for which the former President of Sudan, Omar Al Bashir, is accused before the International Criminal Court.

However, I want to offer some thoughts about an issue that is absent in Sudan’s Application: the legal consequences of genocide, as a grave breach of an obligation arising from a peremptory norm of general international law. This is not an isolated case; it seems to follow a strange pattern in all cases before the ICJ under the Genocide Convention, in which none of the Applicants asked the Court to judge and declare additional consequences for genocide, in the form of an aggravated responsibility for the responsible State or in the form of duties for third States, according the current law of State responsibility.

In this contribution, I will insist in the need of the determination of the consequences of genocide as a serious breach of jus cogens –arguably, with aggression, the most serious– in order to reflect the hierarchic position of peremptory norms in the international legal system.

Genocide as a Serious Breach of jus cogens

There is no doubt: the prohibition of genocide is a peremptory norm. The ICJ itself has recognized it for the first time in its 2006 Judgment in the DRC v. Rwanda case (para. 64), and reiterated it, more importantly, in the 2007 Judgment on the merits in the Bosnia and Herzegovina v. Serbia case (para. 161). That is also the position found in the case law of other international tribunals, like the ICTY (Prosecutor v. Jelisic, 14 December 1999, para. 60; Prosecutor v. Kupreškic, 14 January 2000, para. 20), or the IACtHR (Advisory Opinion OC-26/20, para. 105). The ILC has included the prohibition of genocide in its non-exhaustive list of peremptory norms, annexed to its 2022 Draft Conclusions on jus cogens (Commentary to Draft Conclusion 23, para. 8).

That means that the very commission of genocide (i.e., the violation of the obligation not to commit genocide, identified by the ICJ in its 2007 Judgment, para. 166) is a breach of a peremptory norm. Indeed, it is a serious breach by itself, under the criteria of Article 40(2) ARSIWA. In its Commentary to Article 40, the ILC pointed out: “some of the peremptory norms in question, most notably the prohibitions of aggression and genocide, by their very nature require an intentional violation on a large scale” (ARSIWA, Commentary on Article 40, para. 8).

Therefore, genocide is a serious breach of an obligation arising under a peremptory norm of international law, according to the rules of international responsibility. The logical conclusion is that the legal consequences entailed by it are those enshrined in Article 41 ARSIWA, namely: the duty of cooperation, the duties of non-recognition and not render aid or assistance, and the “other further consequences that a [serious breach] may entail under international law” (Article 41(3)). 

It is true that the existence a regime of aggravated responsibility in international law remains as a contested topic in the legal debate, but at least the consequences enshrined in Article 41(1) and (2) are well grounded in practice and jurisprudence. The ILC reaffirmed them in its 2022 Draft Conclusions (Draft Conclusion 19), and the ICJ itself seems to have finally embraced them (although with certain overlapping or confusion with obligations erga omnes, as it did in the Wall and Chagos advisory opinions) in its 2024 Advisory Opinion on the Legal Consequences Arising from the Policies and Practices of Israel in the Occupied Palestinian Territory. It considered that the right to self-determination constitutes a peremptory norm (in cases of foreign occupation such as that case, para. 233), which was violated by Israel (para. 274), and, “in view of the character and importance of the rights and obligations involved” (para. 279), it stated that all States have the obligation to cooperate (with the United Nations, para. 275), the duty of non-recognition and the duty not to render aid or assistance (para. 279). 

Even the duty to cooperate to bring to an end serious breaches, which in 2001 was considered progressive development by the ILC, it is now recognized under international law, according to the 2022 Draft Conclusions (Commentary on Draft Conclusion 19, para. 2). 

The Genocide Cases and a Persistent Omission

In its Application, Sudan considers itself 

mindful of the jus cogens character of the prohibition of genocide and the erga omnes and erga omnes partes character of the obligations owed by States under the Genocide Convention.

para. 5

However, the remedies that it seeks do not include additional or special consequences of genocide as a serious breach of jus cogens. Instead, Sudan asks the Court for the fulfilment of the duties of cessation, reparation, and giving assurances of non-repetition by the EAU (Application, para. 68), common to all wrongful acts, according to the ARSIWA. 

As I have pointed out in a previous post on this blog, this is not new. In none of the contentious cases concerning genocide, the Applicants asked the Court a pronouncement on the legal consequences of that serious breach of jus cogens. That was the case of Bosnia and Herzegovina, Croatia, The Gambia and South Africa, although all of them recognized the jus cogens nature of the prohibition of genocide.  

I have to insist in my previous point: this is astounding, since genocide is –with aggression– the paradigmatic example of a serious breach of an obligation arising under a peremptory norm, and the determination of its particular consequences is an important matter of international law.

Fortunately, there is a precedent in a case on jus cogens where the Applicants chose to ask the ICJ a pronouncement on the legal consequences of a serious breach. Although it is a case about torture under CAT, there are no legal differences on this particular issue, since gross and systematic acts of torture are, like genocide, a serious breach of a peremptory norm.

It is the case concerning Application of the Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (Canada and the Netherlands v. Syrian Arab Republic), submitted before the ICJ on 8 June 2023. In a very short paragraph in their Joint Application, Canada and the Netherlands have requested the Court 

to adjudge and declare that Syria has committed a serious breach of a peremptory norm of international law, due to its gross or systematic failure to fulfill its obligation under Article 2 of the Convention against Torture not to commit torture as well as to prevent its officials and other persons acting in an official capacity from perpetrating acts of torture, and determine the legal consequences thereof.

Joint Application, para. 61

I have already underlined the historical importance of this claim, and Prof. Hill-Cawthorne has stressed that it would be a very welcome opportunity for the Court to clarify its views on this issue. I have also gave some reasons to follow this example in the cases currently pending before the ICJ, but now I want to share some thoughts on the issue underlying this position. 

Jus cogens and the Need of a Special Regime of International Responsibility 

What is the point of asserting the jus cogens nature of a norm by one hand, and not to claim additional consequences for its breach by the other? If they do not have special consequences in the field of international responsibility, what is the meaning of the very notion of peremptory norms? Restricting their function to the Law of Treaties (Articles 53 and 64 of the Vienna Convention) seems incompatible with its position in international law. Already in 1976, Roberto Ago, in his seminal fifth report on State responsibility, held: 

it would seem contradictory if the same consequences continued to be applied to the breach of obligations arising out of the rules defined as ‘imperative’ and the breach of obligations arising out of rules from which derogation through particular agreements is permitted.

para. 99

One could argue that the effect of jus cogens in international responsibility is the widening of the right to invoke responsibility, since all States have a legal interest in compliance with them. However, this is an effect of the erga omnes nature of the obligations arising from peremptory norms, which is a closely related, but different concept in international law (see the ILC Draft Conclusion 17).

The importance of peremptory norms in international law and the seriousness of their breaches requires a different regime of international responsibility, with additional consequences for the responsible State and for the international community as a whole. The ILC understood this difference in its commentary to the famous Article 19 of its draft on international responsibility: 

the establishment of a distinction between internationally wrongful acts, based on the difference in importance—for the international community as a whole—of the subject-matter of the obligations breached, and at the same time of the extent of the breaches, will necessarily be reflected in the legal consequences attached to the internationally wrongful acts falling into one or the other of the two categories.

ILC Yearbook 1976, Vol. II, part 2, p. 97

Twenty-five year later, in the commentary to Chapter III of Part Two of ARSIWA, the ILC addressed this issue:

there are certain consequences flowing from the basic concepts of peremptory norms of general international law and obligations to the international community as a whole within the field of State responsibility. […] serious breaches of obligations arising under peremptory norms of general international law can attract additional consequences, not only for the responsible State but for all other States.

ILC Yearbook 2001, Vol. II, part 2, pp. 110-111

This is not a mere theoretical issue: serious breaches of peremptory norms entail additional consequences in the field of international responsibility because their importance to the international community as a whole. As the ILC Draft Conclusion 2 states, peremptory norms “reflect and protect fundamental values of the international community. They are universally applicable and are hierarchically superior to other rules of international law.” This hierarchical superiority has an impact in the rules of international responsibility. Judge Cançado Trindade was particularly aware of this impact in his Reasoned Opinion in the Judgment of the Inter-American Court in the Case of Myrna Mack Chang v. Guatemala:

when the international community professes certain fundamental and higher values, it is necessary to accept the consequence of establishment of a special regime of aggravated responsibility (associated with crimes of State) insofar as there are abridgments of said values or of the rules that protect them.

para. 30

Final Remarks

I understand that the Sudan v. UAE case is complex enough to adding new layers of discussion. Its future is uncertain, mainly due to the jurisdictional issues arising the UAE’s reservation to Article IX of the Convention, but the case is useful as a reminder of the need to taking account the legal consequences of genocide, and of serious breaches of jus cogens in general. When a State brings a case before an international court on a matter as serious as genocide must know that there are fundamental rules and values at stake. The importance of those rules requires an adequate treatment in the pleadings of the consequences of serious breaches of peremptory norms. That would give the ICJ an opportunity to clarify this issue, and to develop further the regime of international responsibility regarding jus cogens.