On March 17, the International Criminal Court announced that it had issued arrest warrants for Russia's president, Vladimir Putin, and its children’s rights commissioner, Maria Lvova-Belova, for war crimes involving the forcible transfer and deportation of Ukrainian children. This is not the first time the court has brought charges against a sitting head of state; in 2009, it sought the arrest of Omar al-Bashir, the now former president of Sudan. But there is no question that the warrant for Putin is the most dramatic moment in the court’s two-decade history, given Russia’s status as a permanent member of the Security Council and the widespread international condemnation of its unprovoked invasion of Ukraine.

Fourteen years on, and despite losing power, Bashir has still not been surrendered to the ICC. That failure has reinforced the most common criticism of international criminal law: namely, that it purports to hold individuals accountable for war crimes, crimes against humanity, genocide and aggression, yet only an infinitesimal percentage of those crimes committed since Nuremberg have resulted in prosecution. Will the international community be able to make the many international crimes committed during Russia’s invasion of Ukraine, including the crime of the invasion itself, the exception?

This article describes the existing venues for prosecuting international crimes, including the ICC and national courts in Ukraine and in other countries, as well as the defendants most likely to face charges before each. As discussed below, the crime of aggression will be the most difficult of all to prosecute. The best hope for justice for Russia’s invasion of Ukraine thus lies in creating a new tribunal.

Existing Options for Prosecuting Crimes

Several venues currently exist for prosecuting the war crimes, crimes against humanity and genocide committed in Ukraine. Most notably, despite Russia not being a member, the ICC has jurisdiction over those crimes because Ukraine has accepted its jurisdiction on an ad hoc basis. Indeed, the current investigation by the ICC's Office of the Prosecutor (OTP) is by far the most ambitious in the court’s history, involving a team of more than 40 investigators, forensic experts and support personnel, many of them seconded to the OTP by various ICC member-states. Even the non-member United States has expressed its willingness to assist with the Ukraine investigation, despite being legally prohibited from donating money and personnel to the court.

Because the ICC does not hold trials in absentia—without the defendant being present—the OTP will be limited to building cases until Putin, Lvova-Belova or another Russian suspect is captured. It could be a while: Putin and Lvova-Belova are not leaving Moscow anytime soon, and although it is not impossible that a Russian general who ordered, say, the massacre of civilians at Bucha will fall into unfriendly hands and be turned over to the ICC, that prospect will remain remote as long as the fighting continues. That said, the OTP is duty-bound to investigate crimes committed by both sides of a conflict. Ukrainian soldiers are believed to have committed a small number of war crimes, such as executing prisoners of war, but no evidence has emerged that such crimes were ordered or tolerated by officers senior enough to attract the OTP’s attention. The OTP may well prosecute Ukrainians if that changes, though, because for the foreseeable future obtaining Ukrainian suspects is likely to be far more feasible than obtaining Russian ones.

It is important to emphasize that prosecuting war crimes, crimes against humanity and genocide committed in Ukraine is not only the purview of the ICC. Universal jurisdiction exists over those crimes, which means that any state with the necessary legislation—more than 160, according to Amnesty International—could prosecute Russian perpetrators in its domestic courts. Although universal-jurisdiction prosecutions remain uncommon, they are becoming an increasingly important part of the international response to atrocity. Just last year, for example, Germany convicted a former Syrian intelligence official of crimes against humanity and sentenced him to life imprisonment. Four states have already initiated universal jurisdiction investigations into war crimes and crimes against humanity committed by Russians in Ukraine—Germany, Sweden, Lithuania and Spain—and nearly twice that number have concrete plans to do so. The Lithuanian investigation is focusing on crimes committed during the siege of Mariupol, including the death of the noted filmmaker and scholar Mantas Kvedaravičius, and the German investigation is focusing on indiscriminate attacks on civilians and the use of cluster munitions, both possible war crimes. The first trial of a Russian defendant outside Ukraine—more about which below—is far more likely to occur at the national level than at the ICC because many states that have a civil-law system, such as Lithuania, permit trials in absentia.

Prosecuting the Invasion Itself and the Leaders Who Started It

The crime of aggression is a different story. Although there is no doubt that Russia’s invasion of Ukraine qualifies, very few options currently exist for prosecuting the high-ranking Russian governmental and military leaders who are responsible for the invasion. The ICC cannot prosecute Russian leaders because the court’s jurisdiction is much more limited for aggression than for war crimes, crimes against humanity and genocide. Regarding those three, the court has jurisdiction whenever a crime is committed on the territory of an ICC member-state or a state that has, like Ukraine, accepted the court's jurisdiction on an ad hoc basis. That is why the OTP can currently investigate war crimes, crimes against humanity and genocide in Ukraine. By contrast, the court has no jurisdiction over acts of aggression committed by nationals of a non-member state—not even when the state that is the victim of the aggression has joined the court or accepted its jurisdiction. That asymmetry is not accidental. On the contrary, excluding non-member states from prosecution for the crime of aggression was vociferously demanded by a coalition of powerful states, particularly the U.S., the U.K. and France.

In principle, it would be possible to amend the Rome Statute to apply the same jurisdictional regime to aggression that applies to the other international crimes. In practice, however, that is not a near-term solution. Activating the crime of aggression with its current narrow jurisdictional regime took states more than 15 years of negotiation. Modifying the aggression amendments might not take that long, but it would not happen quickly. Moreover, it is an open question how many states would even support extending responsibility for the crime of aggression to non-member states. Although member-states would have nothing to fear from such an amendment themselves, they have shown lukewarm interest at best in the crime of aggression. The ICC’s jurisdiction over aggression was activated more than five years ago, yet only 44 of the court’s 123 member-states have bothered to ratify the aggression amendments.

States are also unlikely to prosecute Russian leaders for aggression in their domestic courts. Unlike the other international crimes, it is unclear whether states are entitled to exercise universal jurisdiction over aggression, with most scholars—including the current U.S. war crimes ambassador, who is otherwise a strong proponent of prosecuting the crime of aggression—taking the position that they are not. But even if states are entitled to exercise universal jurisdiction over aggression, it is unlikely that many will. Fewer than 20 have the necessary provision in their criminal codes to do so, and only one of those states, Lithuania, is explicitly investigating the crime of aggression on the basis of universal jurisdiction.

There are also sound reasons to question whether states should prosecute the crime of aggression. To begin with, it is uncontroversial that heads of state, heads of government and foreign ministers are absolutely immune from prosecution in domestic courts. That means no state could lawfully prosecute Putin, Russia's head of government or foreign minister for aggression (or for any international crime, for that matter). States would also find it very difficult to obtain the individuals wanted for aggression and the evidence necessary to convict them. Because aggression is considered a leadership crime—one that can only be committed by high-ranking political officials and military leaders—the suspects that states would want to prosecute for aggression will almost certainly be in Russia, safe from capture. Obtaining evidence would be similarly difficult, because the documents necessary to establish that a suspect was involved in “the planning, preparation, initiation or execution” of the act of aggression—the key element of the crime—would presumably be locked away in filing cabinets and archives somewhere in Moscow.

Creating a New Tribunal

Because of the ICC’s lack of jurisdiction and the limits on national prosecutions, the international community has spent much of the past year trying to create a new tribunal for holding Russian leaders criminally responsible for aggression. Most notably, 47 states have joined Ukraine to form a Group of Friends of Accountability whose central goal is to reach a common position on what a new aggression tribunal should look like. That group—which consists almost entirely of states in Europe and North America—is considering three different types of tribunals. Two would be ad hoc international tribunals along the lines of those for the former Yugoslavia and Rwanda. The first would be created by a multilateral treaty between Ukraine and a group of interested states, while the second would be created by an agreement between the U.N. secretary-general and Ukraine on the recommendation of the U.N. General Assembly. The third type of tribunal, by contrast, would be a hybrid tribunal consisting of both Ukrainian and international elements. That tribunal would form part of the Ukrainian judicial system, but it would be supported by an international organization—such as the U.N., EU or Council of Europe—and would feature international judges and prosecutors working alongside Ukrainian ones.

There is no way to know which type of tribunal will win out, but it seems likely that a tribunal will eventually be created. Which type is best is debatable. One critical question is whether any of the tribunals would be able to prosecute Putin, Russia's head of government or foreign minister. The International Court of Justice, the U.N.'s main judicial organ, has made clear that personal immunity does not apply before international courts, but there is very little jurisprudence concerning what makes a court “international” if it is not created by the Security Council, as were the ICTY, ICTR and Special Court for Sierra Leone. A coherent legal argument can be made, however, that a tribunal overwhelmingly endorsed by the General Assembly would be sufficiently “international” to set aside personal immunity. Such endorsement has primarily been discussed in the context of the second model described above—an ad hoc tribunal created by an agreement between the U.N. secretary-general and Ukraine—but there is no reason why such endorsement would not also render international a treaty-based or hybrid tribunal.

Personal immunity for aggression, of course, would only be an issue if Putin, Russia's head of government or foreign minister is captured while still in power. That seems exceptionally unlikely, at least in the short term. Indeed, although a new aggression tribunal would almost certainly enjoy greater resources and greater cooperation from the international community than a purely national court, all three types of tribunal would still likely struggle to obtain suspects and evidence—for all the reasons previously mentioned. That consideration counts in favor of a hybrid tribunal, because it would be quicker, easier and cheaper to add a court to the already functioning Ukrainian judicial system than to create a new ad hoc tribunal from scratch. Even with significant international support, an ad hoc tribunal would take a couple of years to get up and running.

Selective Justice

Any new aggression tribunal will inevitably face allegations of selective justice. Some of the Western states most active in the Group of Friends—most notably, the U.S., U.K. and France—are the same states whose efforts led to excluding non-ICC members from prosecution for the crime of aggression. Moreover, although Russia’s invasion of Ukraine might be the most flagrant crime of aggression committed since World War II, Group of Friends states have committed their own crimes of aggression. To mention one much discussed example, this month marks the 20th anniversary of the invasion of Iraq, a flagrantly unlawful act of aggression that many states and scholars also consider criminal, particularly those in the Global South. Needless to say, no Western government official or military officer was ever prosecuted for their role in the Iraq invasion, nor were such prosecutions ever seriously contemplated. Given those factors, it is not surprising that many states in the South view efforts to create a tribunal limited to prosecuting Russian aggression as further proof that the West cares about aggression only insofar as it is not committed by one of their own.

A Few Words About Ukraine’s Judicial System

Where is Ukraine in all of this? The short answer: extremely active in pursuing accountability. Ukraine has jurisdiction over any international crime committed on its territory, and it has already convicted more than two dozen Russians—mostly relatively low-ranking soldiers—of war crimes such as murder, rape and attacking civilian objects. It has also brought charges against nearly 250 more, a number that will no doubt rise significantly over time. According to Ukraine’s prosecutor-general, Ukraine has registered 65,000 war crimes since the invasion began.

Unfortunately, Ukraine has convicted Russian defendants without the defendant being present and has made clear that it intends to conduct additional trials in absentia. International law does not prohibit in absentia trials, but they are opposed by human-rights groups because they rarely fully respect a defendant’s fair-trial rights. International law also imposes a number of strict procedural requirements on in absentia trials—such as retrial upon capture if there is any doubt that the defendant knew of the earlier proceedings—that are not adequately respected by Ukraine’s Criminal Procedure Code.

Ukraine is also moving forward with plans to prosecute the crime of aggression, having ostensibly identified more than 600 Russian suspects. Although Ukraine has the legal right to do so—as long as it does not attempt to prosecute Putin, Russia's head of government or foreign minister, who are absolutely immune from jurisdiction in national courts—there are reasons to question the wisdom of such prosecutions. Some of those reasons, which were discussed above, apply to any state that attempts to prosecute aggression. But there is also a Ukraine-specific one: the relevant provision in the Criminal Code does not limit responsibility for aggression to individuals who qualify as “leaders” under international law. Prior to the 2022 invasion, Ukraine convicted three individuals of the crime of aggression who did not satisfy the international definition: two low-ranking Russian soldiers and Viktor Yanukovych, who was no longer the president of Ukraine when he asked Russia in 2014 to send troops into the country. Even more problematically, the Office of the Prosecutor General has stated that the 600+ aggression suspects include “deputies” in various ministries, “heads of law enforcement agencies” and “instigators of war and propagandists of the Kremlin.” It is exceedingly unlikely that any of those individuals satisfy aggression’s leadership requirement.

Given the problems with domestic aggression prosecutions, it is encouraging that Ukraine is committed to creating a more international tribunal that can prosecute the crime of aggression. Ukraine clearly prefers the two ad hoc models discussed above, although it has never explicitly rejected the idea of a hybrid tribunal based in its own judicial system.

Looking Ahead

To date, few Russians and no Ukrainians have been held accountable for international crimes committed in Ukraine. Nevertheless, because prosecuting atrocities or aggression is very difficult while fighting still rages, it is too early to add Ukraine to the list of armed conflicts in which the commission of international crimes was met with impunity instead of enforcement. Enforcement mechanisms do exist, and at no time since Nuremberg have states and international organizations been so committed to bringing the guilty to justice. Ukraine may yet prove, then, that the international community can avoid impunity when it really wants to.

Opinions expressed herein are solely those of the author, unless otherwise stated.

Photo shared by Lonpicman under a CC BY SA 3.0 license.