In July 2014, transatlantic powers unexpectedly cooperated on adopting economic sanctions against Russia. Who led the community on the issue of sanctions and why? Why did followers agree to go along considering the costs involved? International Relations theories have neglected the study of international leadership as a cooperation process, and do not explain how a leader emerges and why. This article’s main contribution is to build and test a Cognitive-Affective Theory of international leadership. I argue that shared Cold War frames empowered American leadership and that the emotional resonance of a shocking event, the shooting down of flight MH17, pushed transatlantic allies to converge on the issue of sanctions.
