A Path from Ukraine to Iran: A Special International Tribunal for Criminal Prosecution of Israel’s Aggression

[Savalan Mohammadzadeh is a PhD candidate in public international law at Allameh Tabataba’i University, Tehran, Iran and secretary of the Youth Committee of the Iranian Association for United Nations Studies (holding special consultative status with the ECOSOC).

Mohammad Mehdi Seyed Nasseri is a researcher at the Center for Ethics and Law Studies, Shahid Beheshti University, Tehran, Iran and lecturer in international law at the same university. He holds a PhD in public international law from Islamic Azad University, UAE Branch (Dubai).]

On 13 June 2025, Israel launched a large-scale military operation against Iran, targeting its nuclear program, which constitutes a clear act of aggression. During this operation, various Iranian facilities, scientists, and military leaders were attacked. Subsequently, during a conflict lasting twelve days, numerous attacks on civilian targets were also reported. According to Iran’s Ministry of Health and Medical Education, Israeli attacks resulted in approximately 627 deaths and 4,935 injuries. Since the onset of these attacks, numerous legal scholars have analyzed the issue from multiple angles of international law, particularly jus ad bellum (see here, here, here, here, and here) and jus in bello (see here, here, and here). However, the topic has received less attention from the perspective of international criminal law. While potential war crimes and even crimes against humanity may be implicated, the primary focus of this post is on the crime of aggression.

Given the serious challenges and limitations – similar to those encountered in the Ukrainian case (see for example here and here) – in prosecuting perpetrators of the crime of aggression related to Israel’s attack on Iran through other jurisdictional pathways such as domestic courts and the International Criminal Court (ICC), this post will focus solely on assessing the feasibility of prosecuting such perpetrators via the establishment of a special international tribunal. The recent establishment of the sole example of such a special international tribunal for the crime of aggression, following the agreement between Ukraine and the Council of Europe, further underscores the importance of this inquiry. 

Certainly, before any additional analysis, it’s essential to assess whether Israel’s attack meets the criteria for a crime of aggression under international law.

Does Israel’s Attack Qualify as a Crime of Aggression?

In international law, aggression is classified as an international crime. Although it stems from the broader prohibition of use of force under Article 2(4) of the UN Charter, aggression is a crime with specific legal elements. (For more information on the historical background of the criminalization of aggression, see here, pp. 3-75; and here, pp. 19-271.)

The determination of whether Israel’s invasion of Iran qualifies as a criminal act of aggression requires analysis of two issues: whether it involves a use of force that violates Art. 2(4) of the UN Charter, and whether that use of force gives rise to individual criminal responsibility. As the majority of scholars agree (for example, see here and here), Israel’s attack on Iran is a prima facie breach of Art. 2(4). The next question is whether Israel’s unlawful invasion of Iran qualifies as a criminal act of aggression. It is important to note here that the crime of aggression in the Rome Statute is broader than the crime of aggression under customary international law. The Rome Statute’s definition is straightforward: a criminal act of aggression is “an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the Charter of the United Nations,” with “act of aggression” defined as any act that violates Art. 2(4) of the UN Charter. The customary definition is narrower, although its precise contours are debated. As catalogued by Kress, possible definitions include an act intended to annex territory or subjugate the victim state; an act intended to acquire territory, appropriate assets, or bring about change in the government or foreign policy of the victim state; an act intended to alter the victim state’s status quo by attacking its military, governmental, or economic institutions; or an act intended to establish a military occupation in the victim state (here, p. 1-4).

Israel’s invasion of Iran would qualify as a criminal act of aggression under either definition. In terms of custom, the invasion may satisfy some of the afore-mentioned definitions. For example, based on statements by Israeli officials (notably, see here and here), it can be argued that one of Israel’s objectives in attacking Iran was the change of the Islamic Republic regime. Moreover, as another instance, attacks against scientists and peaceful nuclear facilities, as well as other civilian infrastructure – combined with the targeting of Iran’s senior military commanders and extensive operations by thousands of proxies inside Iran – persistently undermine the security and economic structure and may alter the Iranian state’s status quo. 

 In terms of the Rome Statute, given that any violation of Art. 2(4) qualifies as an aggressive act, the only question would be whether the invasion constituted a “manifest” violation of Art. 2(4) in terms of its character, gravity, and scale. Although the manifest-violation test is notoriously vague, It is beyond doubt that the armed strike launched by Israel in the war under consideration in this study had notable seriousness and was conducted throughout a sizable portion of Iranian territory (including nearly 18 provinces of Iran). The invasion of another state’s territory, the bombardment of another state’s territory was carried out; it was unambiguously illegal under the UN Charter; it was a particularly grave breach of the UN Charter because it was intended to bring about regime change. Consequently, it appears that the criteria for character, gravity, and size are all satisfied (see here, p. 7; and here, p. 4). Of course, It seems that a strong argument can be made that the satisfaction of two of the three components would be sufficient to allow a court to conclude that a use of force amounted to a manifest violation of the Charter. However, such a conclusion should not be taken to suggest that the satisfaction of two components should automatically lead to a finding that the threshold has been met. A court must always look at all three components, although they need not all be present to the same degree (here, p. 160).

Establishing a Special International Tribunal: Two Contending Legal Paradigms

Generally, two models for establishing a special international tribunal can be envisaged: (1) establishment within the framework of the United Nations – either through a Chapter VII Security Council resolution or by concluding a treaty between Iran and the UN based on a General Assembly recommendation – and (2) establishment by concluding an international treaty outside the UN framework. Regarding the establishment of a tribunal through a Chapter VII Security Council resolution, given the likelihood of a veto, such an outcome appears unattainable. With respect to the other options, two divergent approaches exist among legal scholars, centered principally on the challenge of immunity of state officials – encompassing both functional immunity and, more critically, personal immunity. Subsequently, these two approaches will be subjected to rigorous examination.

A Special International Tribunal with the Authority to Set Aside Immunities 

According to one approach, a tribunal established via any of the above-mentioned pathways could potentially possess a sufficiently international character to disregard immunities in the prosecution of international crimes (see, among others, here, p. 7). This approach seems valid when considering functional immunity and its exclusion before such a tribunal.

The International Law Commission (ILC) has examined whether individuals accused of international crimes may invoke functional immunity before foreign courts. According to the ILC, functional immunity does not apply in criminal proceedings before foreign national courts for six international crimes: genocide, crimes against humanity, war crimes, apartheid, torture, and enforced disappearance (see here, pp. 190-191). Notably, the ILC deliberately excluded the crime of aggression from this list. The primary reason offered was that prosecuting an official of another state for the crime of aggression before a national court would require the court to determine whether the other state committed an act of aggression – a determination considered incompatible with the principle of sovereign equality of states. Thus, the ILC did not exclude the crime of aggression from the list of international crimes to which functional immunity does not apply; rather, it stated that under international law no national court has jurisdiction to try accused persons for this crime except the aggressor state itself. However, if one accepts that the crime of aggression can be prosecuted by other states, there seems no reason to treat it differently regarding functional immunity than other international crimes (see here, pp. 11-12).Therefore, it can be argued that individuals accused of the crime of aggression cannot invoke functional immunity before foreign national courts. Since the absence of functional immunity for such accused persons in national courts is accepted under international law, and given that states may delegate their jurisdiction over international crimes to an international court, including a special international tribunal, this possibility (non-applicability of functional immunity) applies a fortiori to international courts –even if the accused holds official capacity in a state that has not consented to the court’s jurisdiction.

Yet, the more significant issue concerns personal immunity. The question is whether a tribunal established via the above-mentioned pathways can possess such an international character that personal immunity would not be applicable in prosecuting international crimes before it. Proponents of this approach argue that a group of states may establish a tribunal to prosecute the crime of aggression where even personal immunity is not recognized. These scholars contend that, according to international jurisprudence, personal immunities do not bar the criminal prosecution of senior officials for international crimes before international criminal courts – which act on behalf of the international community as a whole. This also clearly includes a proposed special tribunal for the crime of aggression that would be established by a UN General Assembly recommendation (see here, and also here, here, here, here, here). 

However, they acknowledge that for a tribunal to have international character, two conditions must be met: first, the tribunal must be established “under international law,” and second, it must sufficiently reflect the “will of the international community as a whole” to prosecute crimes under customary international law. In the case of establishing a tribunal by treaty between a state and the UN based on a General Assembly recommendation, since the tribunal is created by such a treaty (which constitutes a source of international law), its establishment is “under international law.” Moreover, since it is established pursuant to a General Assembly recommendation, it reflects the “will of the international community as a whole” to prosecute crimes based on customary international law. Consequently, such a tribunal has an international character, and personal immunity would not apply before it (see here). Similarly, if a special tribunal is established via an international treaty outside the UN framework, it would also possess international character. But For such a tribunal to be considered sufficiently international so that personal immunity cannot be applied before it, the founding treaty must, like the Rome Statute, be open to all states worldwide and require ratification by at least 60 states to enter into force (see here).

Is Personal Immunity an Obstacle for a Special International Tribunal?

In contrast to the previous approach, another one argues that aforementioned pathways for establishing a special international tribunal cannot overcome the challenge posed by immunities –particularly personal immunity – in prosecuting international crimes.

The view that personal immunities cannot be invoked before international criminal courts derives from the International Court of Justice’s judgment in the Arrest Warrant case (para. 61). Unfortunately, the Court never explained why international criminal courts are not required to respect personal immunities or what precisely qualifies a criminal court as “international”. For some courts, the explanation is relatively clear: Nazi officials were not entitled to personal immunity before the International Military Tribunal because the Allied Control Council, acting as the German government after the war, implicitly waived it. Defendants before the International Criminal Tribunals for the former Yugoslavia and Rwanda also were not entitled to personal immunity because those tribunals were established pursuant to binding Chapter VII Security Council resolutions. Moreover, accused persons who are nationals of ICC states parties enjoy no personal immunity before the ICC because states implicitly waive their officials’ immunities by ratifying the Rome Statute (see here, p. 4).

According to proponents of this approach, states cannot impose obligations on third states without their consent through a treaty, and even if states could delegate jurisdiction to an international court, they cannot thereby circumvent the personal immunity of officials of third states that did not participate in creating that court (see here). The ICJ in Arrest Warrant clearly held that states do not have the power to ignore the personal immunity of officials of other states – even when those officials are reasonably accused of committing international crimes. A fortiori, states cannot create a court empowered to override the personal immunity of officials of non-member states (see here, p. 4). In other words, states themselves essentially lack the authority to waive personal immunity and consequently cannot delegate such authority to an international court.

Therefore, following this approach, it can be argued that personal immunities enjoyed by heads of state under customary international law cannot be disregarded before a special tribunal – even if such immunities are declared inapplicable by the General Assembly or through a treaty concluded between the UN and Iran. It is well recognized that the General Assembly may adopt binding decisions within the internal framework of the United Nations but lacks the authority to make any binding decisions in its external relations. Accordingly, GA does not have the power to impose obligations on member states to take specific actions or compel them to implement decisions within its legal mandates. This limitation stems from the absence of a provision analogous to Article 25 of the UN Charter, under which members consent to accept and carry out Security Council decisions. Consequently, the General Assembly cannot impose obligations on UN member states to waive the personal immunities that afforded to Troika members under customary international law (see here). Hence, if the General Assembly initiates negotiations and concludes a treaty with Iran regarding the establishment of a special tribunal for aggression, such an agreement would bind only the United Nations, Iran, and other consenting states. Therefore, according to proponents of this view, it remains unclear whether a special tribunal established by the above-mentioned pathways – and not by the Security Council under Chapter VII powers –would have the authority to override the personal immunity of senior Israeli officials. It appears that such a tribunal would be bound to respect personal immunity to the same extent as national courts.

Conclusion

As a synthesis of the two approaches concerning the feasibility of establishing a special international tribunal to prosecute the crime of aggression, it may be asserted that, in the absence of a Chapter VII Security Council resolution or the consent of the accused’s national state to the special international tribunal’s jurisdiction, states may still establish such a court and delegate to it the authority to disregard functional immunity. However, under similar conditions, the possibility of delegating such authority to the said court regarding personal immunities remains ambiguous. It appears that the Special International Tribunal for the Crime of Aggression against Ukraine has also partly followed this approach, as Article 23(4) of the draft statute of this tribunal provides that functional immunity shall not apply before the Special Tribunal. Although Article 23(5) permits an indictment to be drawn up for a person with personal immunity, it prohibits the pre-trial chamber judge from confirming the indictment or advancing the prosecution until such immunity is waived or the official leaves office. Hence, a similar model to the Special International Tribunal for the Crime of Aggression against Ukraine, appears to be the most accessible jurisdictional pathway for Iran as well. The importance of establishing such a court for Iran becomes clear when we consider that Iran’s Supreme Leader, Ayatollah Khamenei, also emphasized the necessity of criminal prosecution of crimes committed by Israel before international criminal tribunals. To credibly claim that international criminal justice is not selectively applied, the international community must strive diligently to realize this pathway as effectively as possible.