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Since late 2021, Russia has massed around 100,000 troops on the border with Ukraine, raising the specter of another use of force against its neighbor. The Russia-Ukraine crisis began in earnest in February 2014, when Russian troops spread out from their Black Sea naval base to take control of the Crimean Peninsula. Russia put forward a variety of familiar legal justifications at the time—intervention by invitation, humanitarian intervention, restoration of Russian borders, and self-defense. In my analysis, none of these attempts came close to excusing a serious violation of the United Nations Charter Article 2(4) prohibition on the use of force. (Mary Ellen O’Connell, The Crisis in Ukraine—2014, in Tom Ruys and Oivier Corten (eds.), The Use of Force in International Law, A Case-Based Approach (2018)).


Originally posted EJIL:Talk!; Blog of the European Journal of International Law.