Can one use emotion at anything other than the individual level of analysis? Emotion happens in biological bodies, not in the space between them, and this implies that group emotion is nothing but a collection of individuals experiencing the same emotion. This article contends that group-level emotion is powerful, pervasive, and irreducible to individuals. People do not merely associate with groups (or states), they can become those groups through shared culture, interaction, contagion, and common group interest. Bodies produce emotion that identities experience: group-level emotion can be stronger than, and different from, emotion experienced as an individual; group members share, validate, and police each others’ feelings; and these feelings structure relations within and between groups in international politics. Emotion goes with identity.