Abstract The western response to Russia's full-scale invasion of Ukraine in February 2022 was unprecedented. The states of the European Union, the G7 and NATO have targeted Russia with sanctions and diplomatic isolation, and furnished Ukraine with military assistance sufficient to ensure the Zelensky regime's survival. These efforts have proven insufficient to dislodge Russia from its occupation of Ukrainian territory. Nonetheless, when launched in the aftermath of the invasion, they were seen (and often justified as) as bold, innovative, and steadfast—a necessary response to a grievous act. What explains this response? In this article we argue that the answer lies in the emotions of guilt and shame for past actions and mistakes in the West's dealings with Russia and Ukraine. Informed by a qualitative discourse analysis of key speeches, statements and interviews with leading western policy-makers (past and present), we regard these two emotions—expressed as apologies and the acknowledgment of mistakes—as important drivers of policy. This article contributes to the bourgeoning literature on emotions in world politics. In addition to offering a coherent explanation of the West's unprecedented response our argument has policy implications. While the admission of wrongdoing is laudable, it can lead to actors overcompensating, resulting in further mistakes and policy failures. Fast-tracking Ukraine into the European Union would be one such error.