Russia's full-scale invasion of Ukraine in February 2022 represents a profound challenge to the post-World War II international legal order, particularly the prohibition on the use of force enshrined in the UN Charter. This article critically appraises the diverse legal responses initiated by the international community and specific actors. It examines the assertion of the invasion's illegality under international law, contrasting it with Russia's purported justifications. The article analyzes actions within the United Nations system (Security Council and General Assembly), proceedings before the International Court of Justice (ICJ), investigations by the International Criminal Court (ICC), the imposition of unprecedented economic sanctions, and efforts towards accountability for international humanitarian law (IHL) violations. While acknowledging the significant mobilization of legal mechanisms, the analysis argues that their effectiveness has been mixed. Political realities, particularly the UN Security Council veto, enforcement limitations inherent in international law, and challenges in ensuring state cooperation, have significantly hampered the ability of legal responses to deter aggression, ensure comprehensive accountability, or immediately restore peace and security, highlighting both the resilience and the fragility of the international legal framework.
