 A final ingredient of sovereignty is territoriality, also a feature of political authority in modernity. Territoriality is a principle by which members of a community are to be defined. It specifies that their membership derives from their residence within borders. It is a powerful principle, for it defines membership in a way that may not correspond with identity. The borders of a sovereign state may not at all circumscribe a “people” or a “nation,” and may in fact encompass several of these identities, as national self-determination and irredentist movements make evident. It is rather by simple virtue of their location within geographic borders that people belong to a state and fall under the authority of its ruler. It is within a geographic territory that modern sovereigns are supremely authoritative.