On Ceasefire Monitoring, Criminal Accountability, and the Choice to Enter a War
If Ukraine and Russia agree to a renewed ceasefire, an international military presence may be possible, but it would not follow automatically. The parties would first need to specify which hostilities must stop, where the line of contact lies, how alleged violations would be investigated, and what would happen after a breach. Any states providing personnel would also need to define the force’s authority, location, protections, and rules for using force.
These proposals answer different questions: how a ceasefire would be observed, how crimes would be judged, and how Ukraine would be defended if the fighting continues.
Accountability requires the preservation of evidence and careful documentation of the experiences of civilians and combatants. The International Criminal Court is already investigating the situation in Ukraine, while Ukraine and the Council of Europe have agreed to establish a special tribunal focused on the crime of aggression. Criminal responsibility must be established for particular acts and individuals. The fact that someone has suffered in the war does not, by itself, establish that another particular person committed a crime. A tribunal can adjudicate responsibility for crimes, but it cannot itself stop an attack or enforce a ceasefire.
Ukraine and Russia are the necessary parties to a ceasefire between them. Outside states and organizations could mediate negotiations, verify compliance, or support agreed security arrangements, but each role would require a defined basis and scope. A UN force would require its own mandate and political agreement; Russia’s position as a permanent member of the Security Council makes that route particularly difficult. Nor would a Council mandate alone settle where personnel could operate or how they would respond to danger.
The United Kingdom, France, and Ukraine have outlined plans for a multinational force as part of broader security guarantees after a ceasefire has been agreed. Those plans do not answer the harder question of what happens if no agreement emerges. Without terms to implement, such a force could not simply begin operating as a ceasefire monitor.
This leaves a different and more consequential question: should other states join Ukraine’s defence directly while the war continues? Ukraine has a right of individual and collective self-defence under Article 51 of the UN Charter, and other states may consider assistance at its request. Direct attacks by their armed forces on Russian forces, however, would make those states participants in the fighting and risk a wider war. That choice cannot be treated as a preliminary step toward monitoring a ceasefire. It must be judged on its own legal basis, likely consequences, and capacity to protect the people whose safety is invoked in its name.