ABSTRACTThe principle of nationality is widely believed to be philosophically disreputable and politically reactionary. As defined here, it embraces three propositions: national identities are properly part of personal identities; they ground circumscribed obligations to fellow‐nationals; and they justify claims to political self‐determination. To have a national identity is to think of oneself as belonging to a community constituted by mutual belief, extended in history, active in character, connected to a particular territory, and marked off from others by its members’distinct traits. Such identities are inevitably partly mythical in nature, yet they answer a pressing modern need, the maintenance of solidarity in large, anonymous societies. They are allied to no particular political programme. They do not require the suppression of minority cultures within the political community. They do not justify a secessionist free‐for‐all. Nor finally does recognition of the role of sentiments in constituting national communities commit us to a subjectivist view of social obligations. Philosophers should recognise the value of these loyalties even if they cannot be rationally grounded in a strong