Enduring groups that seek to preserve themselves, as sacred communities do, face a structural contradiction between the interests of individual group members and the survival interests of the group. In addressing existential threats, sacred communities rely on a spectrum of coercive and violent actions that resolve this contradiction in favor of solidarity. Despite different histories, this article argues, nationalism and religiosity are most powerfully organized as sacred communities in which sacred violence is extracted as sacrifice from community members. The exception is enduring groups that are able to rely on the protection of other violence practicing groups. The argument rejects functionalist claims that sacrifice guarantees solidarity or survival, since sacrificing groups regularly fail. In a rereading of Durkheim’s totem taboo, it is argued that sacred communities cannot survive a permanent loss of sacrificial assent on the part of members. Producing this assent is the work of ritual socialization. The deployment of sacrificial violence on behalf of group survival, though deeply sobering, is best constrained by recognizing how violence holds sacred communities in thrall rather than by denying the links between them.