In May 2026, representatives from 36 countries and the European Union convened in Chisinau, Moldova, to sign an agreement establishing the Special Tribunal for the Crime of Aggression Against Ukraine. This development marks a significant step in international efforts to address the legal consequences of initiating war, a subject historically left unadjudicated since the post-World War II trials at Nuremberg and Tokyo.

The tribunal, created in response to Russia’s full-scale invasion of Ukraine in 2022, aims to hold accountable those responsible for acts of aggression, addressing a longstanding gap in international law. Despite clear prohibitions against aggression enshrined in the United Nations Charter, enforcement mechanisms have often been ineffective. Russian President Vladimir Putin’s actions demonstrated that some leaders perceived opportunities to act with virtual impunity—a gap this new tribunal seeks to narrow.

The International Criminal Court (ICC) has previously issued arrest warrants for President Putin and several senior Russian commanders on charges of war crimes and crimes against humanity. However, significant global powers including Russia, the United States, China, India, and Israel are not members of the ICC, diminishing its capacity to enforce rulings against their nationals. Russia has made clear it would not extradite its officials to face charges.

While critics argue that international justice processes are slow and sometimes symbolic, and that selective membership undermines legitimacy, proponents emphasize the importance of maintaining and expanding legal norms and accountability mechanisms. Establishing such institutions, even incrementally, helps generate a record of facts and restricts unchecked power, potentially deterring future aggression.

Observers note that past failures to hold Russia accountable for its 2008 invasion of Georgia contributed to subsequent incursions into Crimea and eastern Ukraine in 2014, culminating in the broader conflict beginning in 2022. The notion that conquest can proceed without consequences risks emboldening similar actions elsewhere unless actively challenged.

Currently, peace negotiations for Ukraine’s conflict do not incorporate accountability measures for those who initiated the war. Ukrainian officials insist that any cease-fire agreement must not come at the expense of justice. Historical precedents, such as the delayed indictments following the Dayton Agreement that ended the Bosnian War, illustrate the dangers of postponing accountability, including the rise of nationalism and revisionist narratives.

The Special Tribunal’s formation involved compromises that left some signatories unsatisfied, but its establishment itself represents a shift in the international community’s approach. Its implications extend beyond Ukraine, signaling a potential deterrent to major powers contemplating unlawful aggression worldwide.

At the United Nations in March 2022, over 140 states condemned Russia’s invasion of Ukraine, yet only 36 joined the tribunal agreement. Advocates stress that participation is less about siding with Ukraine and more about upholding the broader international order designed to protect all states from similar threats.

This tribunal’s emergence reaffirms the principle articulated by Robert Jackson, the chief United States prosecutor at Nuremberg, who reminded that the judgments rendered by courts today shape how history will evaluate those events tomorrow. The choices states make regarding this tribunal will influence not only the immediate conflict but also the precedent future victims and aggressors consider in assessing the durability of the post-1945 international legal framework.