An Unlawful War

Russia's invasion of Ukraine violated the prohibition of force contained in the United Nations Charter and the peremptory norm of general international law prohibiting aggression. The invasion was not an exercise of individual or collective self-defense, or a humanitarian intervention, as Russia variously claimed. The United Nations General Assembly rejected all such claims when 141 member states voted to deplore “in the strongest terms the aggression by the Russian Federation against Ukraine in violation of Article 2 (4) of the Charter” as well as “the involvement of Belarus in this unlawful use of force against Ukraine.” This essay traces the legal implications of Russia's act of aggression, and its violations of international humanitarian law, through international criminal law, international human rights law, and the law of state responsibility. It argues that Russia violates the human rights of every person it kills, and that states are permitted and may be required to provide military assistance to Ukraine and impose economic sanctions on Russia. As Ukraine fights for its survival as an independent state, international law remains both a moral guide and a strategic asset.