EU Joins Special Tribunal to Prosecute Russian Aggression in Ukraine
Acting on behalf of the European Union, the European Commission joined on 15 May 2026 the Enlarged Partial Agreement of the Special Tribunal for the Crime of Aggression against Ukraine. The document establishes the institutional, financial and administrative arrangements for what may prove amongst the most ambitious accountability mechanisms in the post-1945 international legal order.
The jurisdictional gap
The Tribunal has been designed to address a particular gap in international criminal law. The International Criminal Court (ICC) in The Hague is empowered to prosecute war crimes, crimes against humanity, and genocide committed on Ukrainian territory. Yet the ICC cannot, under present 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 particular offence in the relevant configuration.
The Special Tribunal will possess the authority 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 were conducted. 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, characterised 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 received political endorsement from an international coalition of states and international organisations on 9 May 2025 – a date selected for its symbolic resonance, marking 80 years since the surrender of Nazi Germany. The subsequent twelve months have been devoted to translating that political endorsement into ratifiable instruments.
The Council of Europe framework
The Tribunal will be situated 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 throughout the summer. The initial 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 simply as the principal financial and military supporter of Ukraine’s defence, but as the institutional anchor of post-war justice – a role likely to outlast any particular ceasefire or peace agreement. The legal architecture being constructed now will shape the terms upon which any future settlement is judged.
The Claims Commission
Closely related is the Claims Commission, established in parallel to manage 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 ensuring the EU’s contribution is 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, of itself, resolve that question – but it makes it harder to defer indefinitely.
