Hannah Arendt has been criticised for the sharp distinction she drew between the social and political realms, and her application of this distinction to schools. In this paper, I demonstrate that this distinction can be interpreted as a heuristic that Arendt developed to address a tension that she had encountered in her attempt to understand childhood. She understood schools to be spaces that could prepare children for citizenship. However, she also recognised that attempts to prepare children for citizenship threatened two characteristics of childhood: their vulnerability and their natality. Arendt's heuristic can be fruitful for addressing dilemmas in citizenship education in ethnoculturally plural contexts.