This article examines the precedential value of Russia’s ‘special military operation’ against Ukraine in February 2022 for the purpose of interpreting the rules of jus contra bellum. Following the methodology set down by the ICJ in its Nicaragua judgment, self-defence is identified as the legal basis explicitly invoked by Russia in order to justify its operation in Ukraine. The authors then examine closely the reactions by third states with respect to the legality of Russia’s military operation and establish that the legal arguments put forth by Russia – including, more specifically, an innovative reading of the right to self-defence of entities unilaterally recognized as states – have been overwhelmingly rejected by third states. On that basis, the authors conclude that this precedent does not challenge the established understanding of the prohibition to use force in international relations and of its exceptions.