AbstractGenocide is the intentional destruction of a group as such. What makes groups important, over and above the individual worth of the group's members? This paper explores Hannah Arendt's efforts to answer that question, and concludes that she failed. In the course of the argument, it examines her understanding of Jewish history, her ideas about “the social,” and her conception of “humanity” as a normative stance toward international responsibility rather than a descriptive concept.