Against the backdrop of the fourth anniversary of Russia’s full-scale invasion, Ukraine is moving from political statements to practical steps in establishing the Special Tribunal for the Crime of Aggression against Ukraine (STCA). Following the signing of the relevant agreement on 25 June 2025 in Strasbourg between Ukraine and the Council of Europe, the institutional deployment phase of the future court has begun.
This is not merely another international declaration, but the creation of a new body of international justice intended to fill the gap in accountability for the crime of aggression. Although the International Criminal Court investigates war crimes, crimes against humanity, and genocide, its jurisdiction over the crime of aggression is limited due to Russia’s non-ratification of the Rome Statute and the impossibility of obtaining a mandate through the United Nations Security Council.
A Phased Model
A new element is Ukraine’s proposed three-tier model for launching the tribunal, designed to minimize political risks and financial burdens.
The first stage предусматриes the formation of a small advance team that will operate in Strasbourg and the Netherlands. Its task will be to build the tribunal’s internal architecture: drafting rules of procedure, establishing staffing structures, setting security standards, and preparing for the court’s location in The Hague. The European Union has already allocated €10 million for this phase for 2026–2027.
The second stage — the so-called “skeleton tribunal” — will mark the transition from planning to functioning. Judges will be appointed, a registry established, basic procedural mechanisms launched, and an agreement concluded with the host state.
Only after that will the tribunal move to a full operational phase, with courtrooms, security systems, detention facilities, and the ability to issue arrest warrants, including in absentia proceedings.
The Accession Process Has Begun
A particular focus now lies on forming a political coalition. For the enlarged partial agreement within the Council of Europe framework to enter into force, at least 16 states are required. However, the initiators expect support from 25–30 countries to ensure the mechanism’s financial and political sustainability.
Estonia became the first state to complete its internal accession procedure. It is expected that countries outside the Council of Europe may also join the initiative, which could give the tribunal a more global dimension.
Security and Cost — The Main Challenges
Establishing a court that may potentially consider cases against the top leadership of a nuclear power requires enhanced security measures. This includes witness protection, cybersecurity, physical protection, specialized infrastructure, and long-term financing.
These aspects are currently the subject of consultations with states considering joining the agreement.
Political Irreversibility
Ukrainian diplomacy emphasizes that the creation of the tribunal has already passed the point of no return. Each completed stage of institutional development reduces the risk of political obstruction and strengthens the initiative’s legal resilience.
The idea of a special tribunal is viewed not only as a response to the war against Ukraine, but also as an effort to reinforce the international system of deterrence against aggression more broadly. Kyiv is convinced that failure to implement an accountability mechanism for the crime of aggression now would set a dangerous precedent for future conflicts.
Thus, the process is moving from the realm of moral and political assessments into a practical phase of building a new international judicial instrument — with specific timelines, budgets, and state commitments.