COMBATANT IMMUNITY AND THE RUSSIAN-UKRAINIAN WAR: REOPENING THE DEBATE ON A LONGSTANDING DOCTRINE

Background: Russia's invasion of Ukraine has resulted in the largest conflict in Europe since the Second World War, with estimates suggesting that hundreds of thousands of Russian soldiers are implementing the will of the aggressor state. It has long been believed that combatants are immune from criminal prosecution for their actions during hostilities, including the killing of military personnel defending the victim state unless they violate the laws of war. However, this immunity has naturally generated criticism in the Ukrainian legal community. In this article, the authors analyse the critical arguments made by opponents of combatant immunity and seek to clarify the legal and ethical grounds of the controversial doctrine. Furthermore, the well-known debate on the significance of citizenship (nationality) for recognising combatant or prisoner of war status and the liability of defectors is revisited from a new perspective. Methods: The article is based on an analysis of IHL sources, commentaries, state practices, precedents and scientific views on combatant immunity. Additionally, the article examines the practices of law enforcement agencies in Ukraine and the perspectives of Ukrainian criminal law scholars. General scientific methods of cognition (induction, deduction, analysis, synthesis), as well as historical, empirical and systemic-structural methods, are used. The article is structured into three parts. The initial section provides a comprehensive overview of the status of a combatant and their associated privileges within the context of international humanitarian law (IHL), with a particular focus on the ongoing conflict between Russia and Ukraine. The second section delves into the debate surrounding Ukraine's obligation to respect the immunity of the combatant of the aggressor state and offers the authors' conclusions on this matter. The third section addresses the liability of defectors, focusing on the implications of citizenship (nationality) for combatants and prisoners of war (POW). Results and conclusions: Several Ukrainian scholars have expressed their unreserved disagreement with Ukraine's application of the doctrine of combatant immunity to Russian soldiers. In the absence of a direct reference to this exceptional privilege in international treaties to which Ukraine is a party and in light of the a priori unlawfulness of aggression, the critical arguments are not without merit. Nevertheless, we conclude that respect for the immunity of a combatant representing the aggressor state is part of Ukraine's international obligations and has a certain justification. Concurrently, the article acknowledges that the legal and ethical grounds for this are not entirely clear. The question of whether defectors should be recognised as combatants and/or prisoners of war is similarly unclear. Nevertheless, we are convinced that regardless of the answer to this question, the criminal prosecution of defectors for high treason cannot be considered a violation of the immunity of a combatant.