The Russian invasion of Ukraine has created a profound crisis for international criminal justice, as current legal frameworks effectively prosecute war crimes and crimes against humanity but remain deadlocked on the “crime of aggression.” According to the Rome Statute and International Court of Justice (ICJ) precedents, the International Criminal Court (ICC) lacks jurisdiction over this “mother crime” in the Ukraine conflict, leaving a significant gap in holding senior political and military leadership accountable for the decision to wage war.
Why is the “crime of aggression” difficult to prosecute?
The crime of aggression is uniquely tied to leadership, targeting those who exercise effective control over a state’s political or military action. As noted by legal scholar Philippe Sands, failing to prosecute this crime threatens to render it obsolete in international law. Unlike war crimes, which can be investigated by the ICC following a state referral—such as the 40 nations that referred the situation in Ukraine to the court on March 2, 2022—the crime of aggression requires specific jurisdictional triggers that are not present here. Russia is not a party to the Rome Statute, and its veto power in the UN Security Council prevents the referral mechanisms that could otherwise bypass this hurdle.
The ICC is currently participating in a Joint Investigation Team (JIT) alongside Ukraine and several European nations. While this team, supported by Eurojust, is managing over 50,000 registered potential war crimes, its mandate does not extend to the crime of aggression.
Can national courts fill the legal void?
National courts could theoretically use universal jurisdiction to prosecute war crimes, crimes against humanity, and genocide, as 166 states have incorporated these into their domestic laws. However, the ICJ’s 2002 Yerodia decision established that senior government officials enjoy immunity from prosecution by foreign national courts for these acts. This principle of par in parem non habet imperium—meaning an equal has no power over an equal—suggests that sovereign states cannot easily exercise jurisdiction over the leadership of another sovereign state. Consequently, unless a new ICJ ruling clarifies the legality of such actions during an active conflict, domestic prosecutions of Russian leadership for aggression remain legally precarious.
What are the risks of a special international tribunal?
Proposals for a special international tribunal to address the crime of aggression aim to combine Ukrainian law with international legitimacy. Yet, experts like K.J. Heller argue this approach faces two major obstacles. First, it would compete for limited resources and personnel with the ICC, potentially undermining the long-term viability of the world’s first permanent international court. Second, it risks fueling perceptions of “selective justice.” Critics, including various non-Western governments, frequently argue that international criminal law is often applied as a tool of Western power politics, pointing to the lack of similar tribunals for the 2003 Iraq invasion as evidence of a double standard.
Comparative view: Existing vs. Proposed Mechanisms
| Mechanism | Scope | Primary Constraint |
|---|---|---|
| ICC | War crimes, Crimes against humanity | No jurisdiction over aggression in Ukraine |
| National Courts | Universal jurisdiction | Sovereign immunity (Yerodia precedent) |
| Special Tribunal | Crime of aggression | Resource competition & selectivity bias |
What is the most realistic path forward?
The most pragmatic approach may involve utilizing the Ukrainian judicial system to issue rulings that, if supported by the international community, could marginalize the political standing of Russian officials. By potentially issuing European Arrest Warrants, Ukraine—particularly if it advances toward EU membership—could restrict the ability of Russian leadership to travel within Europe. While this does not guarantee incarceration, it serves as a tangible consequence of their actions. Ultimately, the future of international criminal justice depends on whether states are willing to strengthen the ICC by accepting its jurisdiction over the crime of aggression in their own territories, preventing these legal dilemmas in future conflicts.
Follow the International Court of Justice (ICJ) rulings closely. Because the ICJ serves as a primary source of international law, its future interpretation of sovereign immunity in cases of aggression will determine the legal validity of any trials held within Ukraine.
Frequently Asked Questions
Can the ICC prosecute Vladimir Putin for the crime of aggression?
No. The ICC’s jurisdiction over the crime of aggression is limited to member states of the Rome Statute or UN Security Council referrals, neither of which applies to the current conflict in Ukraine.
What is the “mother crime” of the Ukraine war?
Legal observers often refer to the crime of aggression as the “mother crime” because it is the foundational act of invading a sovereign state, which then enabled subsequent potential war crimes and crimes against humanity.
Why not just create a new court for every conflict?
Creating ad-hoc tribunals is expensive and risks creating a perception that international justice is only applied when it suits Western interests, potentially damaging the credibility of global legal institutions.
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