Special Tribunal for the Crime of Aggression against Ukraine

The Special Tribunal for the Crime of Aggression against Ukraine is an ad hoc international criminal court conceived to address a specific jurisdictional lacuna left by the permanent international legal architecture: the inability of the International Criminal Court (ICC) to prosecute the crime of aggression arising from Russia's full-scale invasion of Ukraine that began on 24 February 2022. Although the Rome Statute defines aggression in Article 8 bis and the Kampala Amendments of 2010 activated the Court's jurisdiction over the crime in 2018, Article 15 bis bars the ICC from exercising that jurisdiction where the aggressor state has not ratified the amendments and the situation is not referred by the UN Security Council. Russia is not a party to the Rome Statute, and as a permanent member it can veto any Security Council referral. The Tribunal's legal foundation rests instead on Ukraine's sovereign consent and a multilateral agreement negotiated under the auspices of the Council of Europe, the body that hosts the Register of Damage for Ukraine created in 2023.

Procedurally, the Tribunal's creation followed a deliberate sequence. After Ukrainian President Volodymyr Zelensky and Foreign Minister Dmytro Kuleba publicly proposed a dedicated aggression court in 2022, a Core Group of states convened in early 2023 to draft the constitutive instruments. The Core Group, coordinated with the European Union and Ukraine, produced three documents: a statute defining the offence and the court's competence, an agreement between Ukraine and the Council of Europe establishing the body, and an enlarged partial agreement allowing third states to participate and fund operations. On 9 May 2025 the Core Group reached political agreement on the legal texts in Lviv, and the instruments were formally presented to Council of Europe member states. The Tribunal is structured to sit within or alongside the Council of Europe framework, drawing its judges and prosecutors from participating states, and is expected to be seated in The Hague, building on the precedent of internationalised courts hosted in the Netherlands.

The Tribunal addresses one crime only—aggression as a leadership offence—and is designed to complement, not duplicate, the ICC. Its statute confines jurisdiction to those persons in a position effectively to exercise control over or to direct the political or military action of the Russian state, the so-called leadership clause inherited from the Nuremberg Charter and the Rome Statute. A central and contested feature concerns personal immunities: the prevailing legal view among the Core Group is that the troika of a sitting head of state, head of government, and minister for foreign affairs enjoys personal immunity (immunity ratione personae) before this court while in office, deferring any trial of President Vladimir Putin, Prime Minister Mikhail Mishustin, or Foreign Minister Sergey Lavrov until they leave office, though the Tribunal may issue indictments and conduct investigations in the interim.

By 2025 the institutional architecture had crystallised around the Council of Europe in Strasbourg, with the Core Group meetings convened by ministries of justice and foreign affairs from states including Ukraine, the Netherlands, the Baltic republics, and the European Commission's legal service. The International Centre for the Prosecution of the Crime of Aggression against Ukraine (ICPA), established at Eurojust in The Hague in 2023, functions as an evidence-gathering and case-building hub feeding the eventual Tribunal. The Register of Damage for Ukraine, seated in The Hague with a satellite office in Kyiv, operates in parallel on the reparations track. On 25 June 2025 in Strasbourg, Council of Europe Secretary General Alain Berset and President Zelensky signed the agreement establishing the Tribunal, marking the transition from negotiation to institution-building.

The Tribunal must be distinguished from several adjacent mechanisms. Unlike the International Criminal Court, it is not a permanent treaty court of universal aspiration but a single-situation body limited to the Russian aggression against Ukraine; the ICC retains its own active investigation into war crimes, crimes against humanity, and genocide in Ukraine, and issued arrest warrants for Putin and Maria Lvova-Belova in March 2023 over unlawful deportation of children. The Tribunal differs from the post-1945 International Military Tribunal at Nuremberg, which was imposed by victorious occupying powers, because it derives authority from the victim state's consent and a regional organisation rather than from belligerent occupation. It is likewise distinct from the Register of Damage and any future compensation commission, which pursue civil reparations rather than individual criminal liability.

Controversy surrounds the Tribunal's legitimacy and reach. Critics question whether a court founded on Council of Europe and bilateral agreement, rather than a UN General Assembly resolution or universal treaty, can credibly bind or try nationals of a non-consenting state, and whether immunity for the sitting troika renders prosecution largely symbolic until a change of government in Moscow. The General Assembly's Resolution ES-11/1 of 2 March 2022 condemned the aggression, and Resolution ES-11/5 of 14 November 2022 recommended a reparations mechanism, but no Assembly resolution conferred a Chapter VII-equivalent mandate. Debate also persists over the hybrid versus fully international model, the financing through voluntary contributions, and the risk of trials in absentia.

For the working practitioner, the Tribunal represents the most significant test since Nuremberg of whether the crime of aggression—the so-called supreme international crime—can be prosecuted against the leadership of a permanent Security Council member outside the Council's control. Desk officers tracking accountability files, reparations negotiations, or sanctions policy should monitor the Tribunal's seat, its evidentiary relationship with the ICPA and Eurojust, and the evolving doctrine on immunity, because its precedents will shape every future debate over closing the aggression-jurisdiction gap that the Kampala compromise left open.