Aggressor on trial: what powers will the envisioned Special Tribunal have?
At the end of June, the planned special tribunal for Ukraine cleared an important hurdle. International law expert Robert Stendel explains the background.
Since 2022, plans have been underway to establish a special tribunal to try Russia’s leadership for its attack against Ukraine from a criminal law perspective. This initiative closes a gap in international criminal law, which would otherwise lead to impunity for Russia's war of aggression. In this FAQ, Robert Stendel of the Max Planck Institute for Comparative Public Law and International Law answers key questions about the plans for this novel institution, which achieved a significant milestone on June 25, 2025.
Text by Robert Stendel, with contributions from Michaela Hutterer
Please note: This English version is a translation of the original German interview, which is the authoritative text. Translation by Sarah Gebel
What is a Special Tribunal?
Unlike permanent criminal courts, special tribunals are established ad hoc to prosecute crimes within a specific geographical and temporal scope. These tribunals typically address core crimes under international law, namely war crimes, crimes against humanity, and genocide. Notable examples of such tribunals within the framework of the United Nations include the special tribunals for prosecuting crimes in the former Yugoslavia (1993), in Rwanda (1994), and in Cambodia (2003).
What is the Special Tribunal for Ukraine intended to investigate?
The tribunal shall investigate and prosecute the "crime of aggression”, which is defined as the planning or execution of a war of aggression. The charges are directed at the highest-ranking Russian officials, specifically President Vladimir Putin, Prime Minister Mikhail Mishustin, Foreign Minister Sergey Lavrov, and other individuals from the Kremlin and the Russian military.
Why is this not handled by the International Criminal Court in The Hague?
The International Criminal Court (ICC) lacks jurisdiction over the crime of aggression in Ukraine. Its jurisdiction is based on the Rome Statute, an international treaty. Regarding the crime of aggression, the ICC's jurisdiction is subject to specific limitations: here, not just the attacked state must be a party to the treaty, but also the state whose nationals are accused of being responsible for the aggression. The Russian Federation, however, has not ratified the Rome Statute and is therefore not a party to it.
Are there already proceedings against the Russian leadership?
In March 2023, the ICC issued an arrest warrant, against, among others, President Putin, on charges of war crimes related to the forced deportation of Ukrainian children during the Russian offensive. The ICC has jurisdiction over this case because, for such charges, it is sufficient for the act in question to have been committed on the territory of a state party. Ukraine became a state party in January 2025. Before that, jurisdiction was based on a declaration by Ukraine recognising the ICC's criminal jurisdiction for all acts committed on its territory since 2014.
When did preparations for the Special Tribunal begin?
Discussions among political and legal experts regarding how Russia's aggression against Ukraine can be prosecuted under international criminal law began as early as 2022. In 2023, a "Core Group" of high-ranking legal experts from nearly 40 countries was formed. The goal was to work with Ukraine to develop a legally sound model for a tribunal under international law. Supporting states include the EU member states as well as Australia, Costa Rica, the United Kingdom, Guatemala, Liechtenstein, Norway, and Switzerland. The United States, which had strongly advocated for the establishment of a special tribunal under the Biden administration, withdrew from the group in January 2025. On May 9, 2025, members of the Core Group agreed on important details. On June 25, 2025, the President of Ukraine and the Secretary General of the Council of Europe signed a formal legal agreement in Strasbourg.
How is a Special Tribunal established?
A court requires a legal basis in order to render binding judgements Previous special tribunals were based on United Nations Security Council resolutions or agreements between the UN and the respective states. In contrast, the Special Tribunal for the Crime of Aggression against Ukraine will be based on an international treaty between Ukraine and the Council of Europe. This treaty establishes the tribunal. Additionally, a statute and rules of procedure are needed, as well as further instruments to institutionalize support by other states.
For these purposes, the Core Group prepared drafts of internationally binding documents. Essentially, these drafts include three texts:
- A treaty between the Council of Europe and Ukraine, by which Ukraine transfers its criminal jurisdiction over the crime of aggression to the Tribunal (signed on June 25, 2025).
- A statute of the Special Tribunal regarding procedure and applicable law, as an annex to the treaty (1.).
- An agreement between members and non-members of the Council of Europe, especially regarding financial support for the Special Tribunal (not yet concluded).
Neither of these documents are in force yet. The treaty between Ukraine and the Council of Europe (1.) and the statute (2.) will only enter into force upon ratification of the first treaty by Ukraine and the conclusion of the support agreement. Additionally, a treaty will be required with the state where the tribunal will be headquartered.
Where will the court be located?
No final decision on the court’s location has been made so far, but it will be situated within the territory of a party to the support agreement.
Why Is the Council of Europe Involved?
The Council of Europe was founded after World War II primarily to protect human rights, democracy, and the rule of law. It is headquartered in Strasbourg and comprises 46 countries. It is easily confused with the European Council, which is an organ of the EU. Russia used to be a member of the Council of Europe until 2022.
The Council of Europe has never been involved in the establishment of an international criminal court before. However, researchers have been advocating for the involvement of the Council of Europe in a special tribunal since the outbreak of the war. This was due to the fact that, from an early stage on, the establishment of a tribunal within the UN framework was deemed unlikely. At the same time, a solution involving the Council of Europe has a strong claim for legitimacy: international criminal law faces accusations of applying double standards. Why should President Putin be prosecuted when President George W. Bush was not held accountable for the Iraq War? Such accusations cannot be brought forward against a special tribunal in Europe involving Ukraine and the Council of Europe. Here, the matter at hand is an attack against a member of the Council of Europe, committed by a (former) member of the Council of Europe, and the war is taking place in Europe. In such a scenario, Ukraine exercises territorially based criminal jurisdiction, and the Council of Europe acts within its competencies, while neither of them could prosecute a war far outside of Europe.
Can Ukraine prosecute President Putin and other officials for the Russian war of aggression before its own courts?
Theoretically, this is possible. Ukraine's domestic criminal law prohibits aggressive warfare. Because the war of aggression is occurring on its territory, Ukraine would be entitled under international law to try those responsible for the aggression. However, the personal immunity of the head of state, prime minister, and foreign minister would need to be considered. As long as they are in office, these individuals are protected from criminal prosecution by purely domestic courts of other states.
In any case, such a proceeding would be susceptible to accusations of arbitrariness and lack of independence. Therefore, rule of law considerations suggest incorporating international elements and not conducting the proceedings in Ukraine, to avoid the appearance of victor's justice. Ukraine itself favours an internationalized process in order to bolster the legitimacy of such proceedings.
When is the Special Tribunal expected to take up Its work?
The participating states aim for the special tribunal to commence its work soon. Prior to that, all agreements must enter into force, and sufficient financial support must be secured.
Can President Putin and other officials be prosecuted by the Special Tribunal while still in office?
Heads of state enjoy personal immunity, which means that criminal courts of other states are not permitted to put them on trial, as this would violate the equality of states and disrupt international relations.
According to a position widely shared, this consideration does not apply to international criminal courts, as they exercise the criminal jurisdiction of the international community. For this reason, the ICC was able to issue an arrest warrant against President Putin. It is however indubitable that the special tribunal cannot invoke this reasoning. It exercises the criminal jurisdiction of Ukraine, albeit supplemented by international elements. Because of this issue, Ukraine initially preferred an international solution involving the UN over a regional special tribunal involving the Council of Europe. Ukraine had to abandon this goal due to political realities: a UN Security Council resolution is precluded by a Russian veto, and it is unlikely that a majority for a UN tribunal can be acquired within the UN General Assembly.
What could the Tribunal achieve despite President Putin's immunity?
The forthcoming Special Tribunal is intended to take steps up to the indictment stage but not go further by e.g. issuing arrest warrants (see Article 23, Paragraph 5 of the Statute). Such preparatory actions do not (yet) violate personal immunity.
Officials outside the "troika" of president, prime minister, and foreign minister do not enjoy complete personal immunity, but only so-called functional immunity for actions taken in their official capacity. However, according to a position shared by many states, this functional immunity does not cover the commission of serious crimes. This likely includes the crime of waging a war of aggression (though this is disputed). According to this view, other Russian officials do not enjoy immunity before the special tribunal. The Statute endorses this conception (see Article 23, Paragraph 4 of the Statute).
Can a head of state like President Putin be convicted by multiple courts — the ICC and the Special Tribunal?
A conviction by both courts for war crimes on the one hand and the crime of aggression on the other is conceivable. Both have different jurisdictions and exist side-by-side. A further international treaty is intended to regulate the relationship between the two institutions. In any case, the statute signed in June 2025 obliges the Special Tribunal to cooperate with the ICC.
Is it possible to convict the Russian President, Prime Minister, and Foreign Minister in their absence?
Criminal proceedings in absentia are allowed under certain conditions. This question was debated extensively among the supporting states, as the presence of the accused is a fundamental demand of due process. Since the end of June 2025, it is clear that it will be possible. The statute explicitly allows for proceedings in absentia if the accused has clearly waived the right to be present, or if all attempts to ensure knowledge of and presence at the hearing have been made and the interest of justice demands prosecution (see Article 28, Paragraph 1 of the Statute). Furthermore, according to the Statute, proceedings in the absence of the accused are subject to additional procedural safeguards in order to ensure compliance with rule of law requirements.
Is it conceivable that no conviction will be possible, neither for crimes during the war nor for the attack Itself?
Whether a conviction for the crime of aggression and for other crimes under international law will actually take place is dependent on multiple factors. Crucially, it will depend on how the conflict progresses but also on how the political situation within the Russian Federation develops. Since it is unlikely that the Russian leadership will face the Special Tribunal, it is uncertain whether they will ever be held accountable. However, the Special Tribunal is at least an expression of a large group of states’ willingness to prosecute such acts. Thereby, the states strengthen the general awareness that wars of aggression are not a legitimate political tool but a crime. This sends a strong message to the Russian leadership and other governments in Europe.
Critics argue that the threat of punishment could complicate peace negotiations. However, a peace without criminal accountability for those who initiated the war could encourage the Russian leadership to invade its neighbours again. Furthermore, a special tribunal contributes to the goal of general deterrence: all heads of state will think twice before attacking a sovereign neighbour state. The Special Tribunal will make President Putin's life less comfortable, and it could be particularly valuable if the domestic political situation in Russia were to change one day. In that case, an already established special tribunal could offer support to a new Russian leadership if it wishes to break with the policies of the previous leadership.
