Prepare rather than wait: What should the international tribunal on Ukraine look like, and who will stand trial?

The war in Ukraine, which Russia initiated in 2014 with the occupation of Crimea and the assault on Donbass and escalated with its open invasion from Russian and Belarusian territories in 2022, has shattered the foundations of the modern world order, shattering international norms regarding respect for international law, the inviolability of borders, and the prohibition of the threat or use of force in international relations. Given the gravity of both the aggression itself and of the numerous crimes that aggression has spawned, it is evident that those responsible, including Russia’s highest military and political leadership, must face international justice. However, the specifics of such a tribunal — the legal framework it should adhere to, its location, and the individuals who should stand trial — are far from clear-cut.

The Hague is powerless

Typically, the primary recourse for bringing international malign actors to justice is the International Criminal Court (ICC) in The Hague. Indeed, the ICC is empowered to address all forms of international crimes, which encompass four categories:

• War crimes;
• Crimes against humanity;
• Genocide;
• Crimes of aggression (also known as crimes against peace).

While Ukraine is not a member state of the ICC, it recognized the court's jurisdiction in 2015 according to the ICC Statute. Consequently, the ICC holds jurisdiction over Russian war crimes, crimes against humanity, and acts of genocide committed on Ukrainian soil. Presently, ICC judicial investigators are actively engaged in documenting and gathering evidence, including within Ukraine itself. Still, the ICC faces obstacles to the prosecution of Russia’s leadership for crimes of aggression. Amendments implemented in 2012 restrict the prosecution for such crimes solely to ICC member states — and like Ukraine, Russia is not a party to the ICC. Theoretically, the case could be referred to the ICC by the UN Security Council, but given Russia's veto power as a permanent member of this body, that prospect remains remote.

The ICC does not supplant national judicial systems but intervenes only when a state is unwilling or unable to conduct a proper investigation and prosecute international criminals. Regrettably, Russia exemplifies such a scenario. In a state governed by the rule of law, the onus lies on the state itself to prosecute its offenders. For instance, in the case of the notorious abuses at Abu Ghraib prison in Iraq perpetrated by a group of American soldiers, justice was served through the decisions of American courts, which found 12 U.S. military servicemen guilty and sentenced them to prison terms. Consequently, there was no necessity for the intervention of the International Criminal Court.

However, thanks to the principle of universal jurisdiction regarding international crimes, such cases can be prosecuted even by courts of countries not directly involved in the conflict. Poland, Germany, Lithuania, Spain, and other nations have already initiated investigations into Russian war crimes or have declared intentions to do so. This is crucial because much of the evidence prosecutors are gathering is currently being provided by Ukrainian refugees in European countries. As for Ukraine itself, as of February 13, 2024, the Ukrainian Prosecutor General's Office had registered 121,669 war crimes. This number continues to grow daily, and all information is published on the organ’s official website.

The situation in the occupied territories remains largely uninvestigated, but when it becomes possible to gather evidence there, the number of suspected war crimes is likely to grow two- or threefold. The mass graves near Mariupol alone, visible from satellite imagery, speak volumes. Considering the size of the Russian contingent, it can be assumed that practically all Russian military servicemen at every rank — soldiers and sergeants, junior and senior officers, generals, and the supreme commander-in-chief — have committed war crimes, whether individually or as part of their unit. It is evident that prosecuting such a large number of people will require the involvement of all possible law enforcement mechanisms, both national and international, which must work closely together and coordinate their efforts.

A review of the list of war crimes outlined in Article 8 of the Statute of the International Criminal Court makes clear that Russian occupiers have committed virtually every type of war crime in the book, and they have done so on a massive scale. These crimes range from deliberate killings of civilians and prisoners of war to instances of rape, looting (even of toilets and dog kennels), the deliberate destruction of civilian infrastructure, and the abduction of children as an element of state policy. It is worth noting that the International Criminal Court has already issued an arrest warrant for Russian President Putin and for his Children's Rights Commissioner Maria Lvova-Belova in connection with these crimes.

Why was this specific crime chosen for the initial arrest warrant? The reason lies in the complexity of proving guilt in court, especially given the challenges of collecting evidence during wartime. But in the case of the systematic practice of child abduction, the public statements of Russian officials combined with the presence of Russian laws facilitating the adoption of abducted Ukrainian children, make it possible to argue this case in court without gaining direct access to the territories on which the crimes were committed. Still it is likely that new criminal cases will emerge, potentially leading to reclassifications and additional warrants. For instance, child abduction could be reclassified as a crime against humanity or even genocide.

Why a separate international tribunal?

The idea of establishing a distinct international tribunal to address the crime of Russian aggression in Ukraine arises from the limitations within the ICC regarding this specific offense. Aggression itself is the root cause of numerous other crimes, and it is precisely for the crime of aggression that the highest military and political leadership of a country should be held accountable, as was demonstrated by the post-World War II Nuremberg and Tokyo tribunals. This accountability extends not only to Russia but also to Belarus, given that one form of aggression, as defined by the UN, involves a state allowing its territory to be used by another state to commit aggression against a third state. Russia’s incursion into Kyiv in Feburary and March 2022, routed through Belarus, along with the shelling of Ukrainian territory and the involvement of Russian aviation, make the political leadership in Minsk liable for prosecution right alongside their Russian counterparts.

Still, establishing the authority to hold offenders accountable is easier discussed than done. While special international tribunals for the former Yugoslavia and Rwanda were set up through UN Security Council resolutions, this approach is unfeasible for Ukraine due to Russia’s veto power. This is what happened in the failed attempt to establish a tribunal for the downing of Malaysian Airlines Flight MH17: Russia vetoed the proposal, necessitating that the case be handled by the national court of the Netherlands — with the Russian defendants tried in absentia.

A more viable approach involves creating a tribunal through a treaty signed by the UN and Ukraine on the basis of a referral of the UN General Assembly and the UN Secretary-General, or through a multilateral treaty between Ukraine and other states, with support from the UN. It is important to emphasize that such a tribunal would not compete with or undermine the role of the ICC but rather complement it. The ICC, alongside national courts, can address Russian crimes in Ukraine at a lower level, and it can do so concurrently and in coordination with the international tribunal.

The Nuremberg Tribunal set up after World War II to try top Nazi criminals is the most widely known example of a process initiated to bring German offenders to justice, but it is important to recognize that numerous trials of Nazi criminals also took place in national courts. These included the Auschwitz Trials (Poland), the Riga Trial (Latvia), and the Eichmann trial (Israel).

The idea of establishing a separate ad hoc tribunal for the crime of Russian aggression against Ukraine initially surfaced in an open letter signed by former British Prime Ministers Gordon Brown and John Major along with several scholars and other public figures. This approach was further supported by a resolution of the Estonian parliament, which labeled Russia's actions as genocide against the Ukrainian nation. Over time, this idea of an ad hoc tribunal gained traction through communiques from international conferences in Vilnius, resolutions of the Council of Europe and the European Parliament, and other organizations. In The Hague, the International Centre for the Prosecution of Crimes of Aggression against Ukraine has already been established.

Efforts are underway to draft a treaty and statutes for such a tribunal, and the initiative is supported by a coalition of approximately 40 countries, with more states set to join them. And although legal issues can be endlessly debated, what matters most is the political will of world leaders.

Another option is a hybrid (mixed) court similar to those established in Kosovo (2000), the Special Court for Sierra Leone (2002), the Extraordinary Chambers in the Courts of Cambodia (2004), and the Special Tribunal for Lebanon (2009). In these hybrid courts, international judges collaborate with national judges under the auspices of the national legal system. However, a hybrid tribunal may encounter significant challenges, especially concerning immunity. Since aggression is considered a crime of leadership, the immunity of heads of state or high-ranking officials could ultimately impede the effectiveness of judicial prosecution. This issue does not arise in international tribunals, where such immunities do not apply. There are varying perspectives on this matter regarding hybrid tribunals.

Furthermore, the Constitution of Ukraine prohibits the establishment of extraordinary or special courts, a provision that cannot be amended as long as a state of war exists. A hybrid tribunal theoretically falls under this definition, and the Ukrainian leadership itself has stated that its preference is for an international tribunal, not a hybrid one. Nevertheless, the European Union along with the G7 in general still appear to be leaning towards a hybrid tribunal option as the most realistic approach, despite the attendant obstacles.

Another key factor in determining the form that the fight for justice against Russian war criminals ultimately takes is the ICC prosecutor himself, Karim Khan, who is actively opposing any efforts to establish an international or hybrid tribunal. Khan believes that such a move would undermine the authority of the ICC, yet he has failed to propose a viable alternative. While it is true that setting up ad hoc tribunals poses challenges from legal, political, financial, and technical perspectives, having a permanent international judicial body would eliminate the need for such tribunals. However, given the ICC's limited jurisdiction regarding the crime of aggression, Prosecutor Khan's stance seems unfounded and only serves the interests of Putin and his associates. Considering the extensive volume of Russian crimes committed in Ukraine, there ought to be more than enough work for everyone involved, and talk of competition should be dismissed.

Understanding the prosecution of top leadership

Historically, the first tribunals trying the top leadership of states were the Nuremberg and Tokyo tribunals (officially known as the International Military Tribunal in Nuremberg and the International Military Tribunal for the Far East). Despite criticisms that the courts were little more than “victors’ tribunals,” the courts played a significant role not only in directly punishing criminals but also in shaping the fundamental principles of modern international criminal law.

The so-called Nuremberg Principles were formulated by the International Law Commission in 1950 at the request of the UN General Assembly. The commission did not invent them but rather summarized the Nuremberg Military Tribunal’s work and formulated seven principles reflected in its decision. Although these principles were not initially legally binding, many scholars today consider them to be the norms of customary international law, applicable to all countries.

Furthermore, some of the principles were later incorporated into legally binding documents. For instance, the third principle, found in Article 27 of the ICC statute, applies directly to the man currently sitting atop the Kremlin hierarchy: “The fact that a person who committed an act which constitutes a crime under international law, acted as Head of State or responsible government official, does not relieve him from responsibility under international law.”

And the principle has precedent in the form of tribunals concerning the former Yugoslavia and Rwanda, which sought to hold the top military and political leaders of each country accountable. The destinies of notable figures like Slobodan Milošević, the first president of Serbia (who passed away in a prison cell in The Hague while awaiting judgment), Radovan Karadžić, the first president of the self-proclaimed Republika Srpska, and Ratko Mladić, the commander-in-chief of the forces of this pseudo-state, are familiar even to those far removed from the field of jurisprudence. The latter were both sentenced to life imprisonment for war crimes, crimes against humanity, and genocide.

Less well known is the fact that the International Tribunal for the former Yugoslavia, which operated from from 1997 to 2004, brought charges against 161 individuals, many of whom were convicted. The Rwanda Tribunal, in turn, indicted 96 individuals, including Rwanda's Prime Minister, Jean Kambanda, who received a life sentence for the genocide of the Tutsi people during his time in power. This is significant because, in the choice between an international and a hybrid tribunal, the issue of immunity for high-ranking officials can become pivotal.

To be fair, there have been instances in which similar sentences were handed down by hybrid tribunals. For instance, the Special Court for Sierra Leone sentenced Liberia's President Charles Taylor to 50 years in prison for war crimes and crimes against humanity, effectively a life sentence given his age.

Furthermore, it is worth noting that the Nuremberg and Tokyo tribunals were the only ones in history to hold individuals accountable for crimes against peace (aggression). All other ad hoc international and hybrid tribunals had jurisdiction only over the other three types of international offensess (war crimes, crimes against humanity, and genocide), and the ICC has such jurisdiction only in theory. While it may be possible for a hybrid tribunal to consider the issue of aggression, having a historical precedent on hand is always advantageous.

And of course, given that an act of state aggression cannot be committed without the participation of a country’s military and its political leadership, then the question arises: in addition to Putin and Lukashenko, who else from Russia and Belarus should face prosecution for this offense? In my view, the list must include members of the Russian Federation's Security Council, who decided on the recognition of the pseudo-republics of LNR and DNR (effectively occupational administrations), thus initiating a full-scale invasion. Also implicated are members of both chambers of the Federal Assembly who voted for war in both 2014 and 2022, government officials, top military and intelligence leaders, key propagandists, and oligarchs from Putin's inner circle.

Although the process of establishing an international tribunal may be long and complex, it is crucial to remember the 1968 Convention, which states that there is no statute of limitations for international crimes. Even if a verdict against Putin is rendered against him in absentia, the Russian head of state would still be unable to travel to any country supporting the tribunal without facing immediate arrest, and given the rapidly evolving global landscape, an opportunity to actually physically imprison the man himself could arise tomorrow, even if it seems impossible today. And of course, there's always the possibility that surrendering to The Hague could be Putin's only option if he is to avoid a fate similar to Muammar Gaddafi’s, who fell into the hands not of international lawyers, but of the “grateful people” he had ruled over for more than three decades.

You can find more details on establishing a tribunal in a research paper published in December 2023.