POLITICS
On June 25, Ukraine and the Council of Europe signed an agreement to establish a Special Tribunal focused on prosecuting Russian officials for the crime of aggression against Ukraine. However, Vladimir Putin, who retains immunity while in office, will not be tried anytime soon, and it remains to be seen which individuals will actually be held accountable, even in absentia. The tribunal cannot begin full operations until at least 2026, and the possibility remains that its implementation will be stalled. Still, even in its limited form, the tribunal marks a significant step towards the establishment of the first international court prosecuting the crime of aggression since Nuremberg and Tokyo. And its very existence exerts pressure on the Kremlin.
On June 25, Ukrainian President Volodymyr Zelensky and Council of Europe Secretary-General Alain Berset signed the treaty establishing the Special Tribunal for the Crime of Aggression against Ukraine. Although discussions to set up such a judicial body began in February 2022, it is only now that the plans have taken shape.
What defines the crime of aggression?
In 2010, the ICC states parties adopted a definition for the crime of aggression the “planning, preparation, initiation or execution, by a person in a position effectively to exercise control over or to direct the political or military action of a State, of an act of aggression which, by its character, gravity and scale, constitutes a manifest violation of the UN Charter.” Russia, which at the time was an ICC observer state under President Dmitry Medvedev, fully supported the definition — fifteen years later, Medvedev declared the ICC “a legal nonentity.”
The concept of the crime of aggression is grounded in the belief that illegal war is evil in itself. The International Military Tribunal in Nuremberg described the launching of a war of aggression as “the supreme international crime differing only from other war crimes in that it contains within itself the accumulated evil of the whole.”
Aggressive war, by its nature, violates human rights. The UN Human Rights Committee held in 2019 that every deprivation of life resulting from an act of aggression amounts to a violation of the right to life. International humanitarian law does not classify all killings in wartime as war crimes. Only by prosecuting the crime of aggression can state leaders be held accountable for the killing of soldiers and civilians resulting from an unprovoked attack, even if those deaths resulted from actions that would be seen as acceptable under the laws of war. War crimes, by definition, can be committed by both sides of an armed conflict — and often are. Focusing solely on prosecuting war crimes committed in a conflict that resulted from a clear act of aggression from one side creates a false perception of legal and moral equivalence between aggressor and victim. Hence the necessity of prosecuting the crime of aggression.
Aggression is a “leadership crime” — one for which political and military leaders of the aggressor state are held responsible, along with officials of any co-aggressor states. In the case of Russia’s war of aggression against Ukraine, this includes Belarus and potentially North Korea.
Why was the tribunal controversial?
A special tribunal was deemed necessary because, under current conditions, the International Criminal Court (ICC) cannot independently initiate proceedings for the crime of aggression in Russia’s war against Ukraine. This particular crime falls under a special legal regime, and the only mechanism for referral to the ICC is through the United Nations Security Council — an unworkable solution in this case, as Russia holds veto power as a permanent member of this UN organ. The ICC states parties are scheduled to review amendments to the Rome Statute in early July aimed at closing this loophole. However, those changes, even if adopted, will likely apply only to future acts of aggression, not to the ongoing war in Ukraine.
Europe struggled for years to reach a consensus on a tribunal. The idea was first publicly proposed just four days after the start of Russia’s full-scale invasion, when University College London law professor Philippe Sands published an op-ed in the Financial Times. His proposal was swiftly endorsed by dozens of legal scholars and political leaders, including former UK Prime Minister Gordon Brown, who co-authored a declaration supporting the initiative. The idea went on to gain backing from the Ukrainian government and several other states.
Ukraine initially pushed for a full-fledged international tribunal modelled on the post-conflict ad-hoc tribunals established in the 1990s to try persons responsible for the atrocities in of Rwanda and the former Yugoslavia. However, the proposal faced immediate criticism, including from members of the Group of Seven (G7) — particularly the United States. While the Biden administration supported the idea of holding Putin and his inner circle accountable for the crime of aggression, it advocated for a court based in Ukraine with international participation. U.S. officials argued that the immunity enjoyed by Putin and other senior Russian officials posed a clear legal obstacle to prosecuting them in an international forum.
There were also concerns about the feasibility of garnering broad international support, especially outside Europe, and securing a strong majority in the UN General Assembly, which would have needed to endorse the creation of such a tribunal. The “hybrid tribunal” model eventually approved by the G7 countries, including the UK and Germany, was seen by some observers as a diplomatic compromise.
Beyond Europe, the idea of a tribunal drew objections from many countries in the Global South, where it was perceived as a “court against Russia” — set against the backdrop of Western impunity for illegal military actions, and especially U.S.-led invasion of Iraq in 2003. There were also concerns about the feasibility of garnering broad international support, especially outside Europe, and securing a strong majority in the UN General Assembly, which would have needed to endorse the creation of such a tribunal.
The International Criminal Court expressed unexpectedly lukewarm support for the tribunal idea. Prosecutor Karim Khan called for a “consolidation” of efforts within the ICC framework, effectively characterizing the tribunal project as a dilution of prosecutorial efforts. Observers, however, saw this as a sign of institutional competition and a “turf war.”
The Council of Europe’s regional international tribunal ultimately emerged as a compromise solution. In 2023, a Core Group on the tribunal was formed, bringing together representatives from around 40 countries: the EU member states, the United States, the United Kingdom, Australia, and Switzerland. However, following Donald Trump’s return to the White House, the United States withdrew from the initiative.
The group’s efforts produced three key documents: a draft agreement between Ukraine and the Council of Europe, the Tribunal’s statute, and what is referred to as an “enlarged partial agreement,” which governs the tribunal’s operations. Membership is open to Council of Europe members (though participation is not mandatory) as well as third countries.
What do we know about the structure of the future tribunal?
Documents published by the Council of Europe indicate the following parameters for the special tribunal:
- The tribunal will be established through an international treaty between Ukraine and the Council of Europe, with membership open to other states.
- It will apply international law — including the ICC’s definition of aggression, and, as the last resort, Ukrainian criminal law when necessary.
- The Judges and a prosecutor will be selected by a managing committee from participating states.
- Ukraine’s attorney general will provide files on suspects. If the prosecutor finds the legal and evidentiary basis then investigations can be launched and indictments can be submitted to judges. The prosecutor cannot initiate cases independently.
- The tribunal is likely to be based in The Hague, though the final hosting location will be determined via future bilateral agreements.
- It can hold trials in absentia, but only for individuals not covered by immunity. This means that the so-called “troika” of top officials — the head of state, the head of government (prime minister), and the foreign minister — cannot be prosecuted while they remain in office, though charges against them can be prepared at any time.
Trials of Vladimir Putin and Sergey Lavrov will only be possible after they leave their official positions, as their immunity remains in effect while they are in office.
A document published by the Council of Europe “expresses hope” that work on establishing the tribunal will be completed by 2026. However, the feasibility of that timeline depends on the actions of participating states, which must still ratify the agreement, approve the budget, and carry out other necessary steps.
What questions remain unanswered?
While the new special tribunal on the crime of aggression against Ukraine will not be able to hold trials in absentia for Russia’s top leadership — the so-called “troika” — this does not mean that it cannot investigate their actions. It appears the architects of this compromise aimed to sidestep the legal challenges of head-of-state immunity by imposing restrictions on the “not-fully-international” body.
Legally, the decision conflates two distinct issues: trials in absentia, and immunity. Immunity is either present or it is not. If the head of state is immune before an international tribunal — a claim that remains legally debatable — then the prosecution of that individual is barred — both in person and in absentia.
Recognizing the immunity of a dictator before an international tribunal could send a dangerous signal. Leaders like Vladimir Putin, Alexander Lukashenko, and Kim Jong Un are de facto lifelong autocrats. In effect, by acknowledging their immunity, the tribunal’s founding states not only legitimize their rule but also offer them a blueprint for avoiding international justice: cling to power at any cost. In Putin’s case, that cost is a continuation of the current war of aggression.
Moreover, given that all states involved in the tribunal’s founding group are also part of the ICC, the compromise agreed to on June 24 undermines the credibility of arrest warrants already issued by the International Criminal Court (ICC) — particularly those against Putin and Israeli Prime Minister Benjamin Netanyahu. It remains unclear who exactly the tribunal’s creators envision as defendants, especially since aggression is legally classified as a “leadership crime.” Still, the tribunal will retain the ability to prosecute individuals who have left office, as well as key ministers and military commanders who remain in positions of secondary authority in Moscow and Minsk.
The tribunal’s dependence on Ukrainian officials to determine the list of suspects could also become a source of criticism and raise legitimacy concerns. It is crucial the tribunal not repeat the mistakes of the Special Tribunal for Lebanon, which was dissolved on December 31, 2023, after issuing only a single conviction in absentia, one related to the 2005 assassination of former Lebanese Prime Minister Rafik Hariri.
Is a “compromise” tribunal better than none at all?
Delays in the tribunal’s formation risk eroding support for its very existence, and there is a real chance it could prove ineffective. But international criminal justice is always a long game. When it comes to prosecuting leaders of powerful states, success stories are rare. Many dictators and aggressors have evaded trial altogether. Yet even a limited tribunal can have a meaningful impact. It may become the first genuine judicial process for the crime of aggression since Nuremberg and Tokyo, keeping global attention on the issue.
The tribunal could also play a vital role during a potential future political transition in Russia. Cooperation with the tribunal may become a precondition for reintegrating Russia into the international community. Indeed, comprehensive justice, including accountability through this tribunal, would likely only be possible following such reintegration. Its creation avoids the false binary between inaction today and hypothetical justice “tomorrow.”