EU Joins Special Tribunal to Prosecute Russian Aggression in Ukraine
The European Commission, acting on behalf of the European Union, joined on 15 May 2026 the Enlarged Partial Agreement of the Special Tribunal for the Crime of Aggression against Ukraine. The document sets out the institutional, financial and administrative modalities of what may become one of the most ambitious accountability mechanisms of the post-1945 international legal order.
The jurisdictional gap
The Tribunal is designed to close a specific gap in international criminal law. The International Criminal Court (ICC) in The Hague can prosecute war crimes, crimes against humanity, and genocide committed on Ukrainian territory. But the ICC cannot, in current circumstances, prosecute the crime of aggression committed by Russian leaders against Ukraine, because neither Russia nor Ukraine has accepted the Court’s jurisdiction over that specific offence in the relevant configuration.
The Special Tribunal will have the power to investigate and prosecute senior Russian political and military leaders for the crime of aggression – the original international crime under which the 1945 Nuremberg trials proceeded. As the Commission noted in its accompanying communication, “the Special Tribunal and the Claims Commission will be the fundamental international bodies ensuring full accountability for the international crimes, and compensation for damages, committed in Ukraine.”
“A significant step forward”
The Commissioner for Democracy, Justice, the Rule of Law and Consumer Protection, Michael McGrath, framed the decision in unambiguous terms: “Today marks a significant step forward in delivering justice for the people of Ukraine. A true, just and lasting peace cannot exist without justice and accountability.”
The founding legal texts of the Tribunal were politically endorsed by an international coalition of states and international organisations on 9 May 2025 – a date chosen for its symbolic resonance, marking 80 years since the surrender of Nazi Germany. The intervening twelve months have been spent translating that political endorsement into ratifiable instruments.
The Council of Europe framework
The Tribunal will be seated within the framework of the Council of Europe, with the Enlarged Partial Agreement open to non-Council-of-Europe states. Ratifications are now expected to proceed in parallel across European capitals through the summer. The first practical questions – appointment of prosecutors and judges, evidentiary protocols, the relationship with the ICC and with national jurisdictions – will dominate the institutional agenda over the coming year.
Beyond the headline
For the European Union, the strategic dimension of the project extends beyond accountability for past acts. The EU’s accession positions it not merely as the principal financial and military backer of Ukraine’s defence, but as the institutional anchor of post-war justice – a role likely to outlast any specific ceasefire or peace agreement. The legal architecture being built now will shape the terms on which any future settlement is judged.
The Claims Commission
Closely related is the Claims Commission, established in parallel to handle compensation for damages caused by the Russian invasion. The two institutions are designed to function in tandem: the Tribunal addressing individual criminal responsibility, the Claims Commission addressing state responsibility for damages. The combination represents the most comprehensive accountability apparatus assembled since the post-1945 European settlements.
The political economy
Funding is the next question. The Commission has committed to making the EU’s contribution proportionate to its declared political backing. Member-state contributions will be sought during the ratification cycle. Russia’s frozen assets in Europe – estimated at over €200 billion, with €190 billion held at Euroclear in Brussels – continue to circle around the project. Whether and how these assets are mobilised for reparations remains contested, with German and Belgian reservations balanced against more aggressive positions from the Baltic states, Poland and the Nordic capitals. The accession of the Union to the Tribunal does not, by itself, resolve that question – but it makes it harder to defer indefinitely.
