Most analysts agree that democratic theorists have not offered a persuasive answer to the question of how the boundaries of a demos, a democratic people, should legitimately be defined. Some contend that boundaries should be maintained in ways that preserve sufficient sense of common identity to sustain support for redistributive policies. Many others endorse the 'principle of all affected interests,' but it has been widely criticized as unrealistically destructive of too many existing community boundaries. This essay argues for an alternative 'principle of constituted identities.' It holds that, subject to certain important qualifications, modern constitutional democracies, at least, are morally obligated to extend the option of full membership to all those whose identities have been substantially constituted through such regimes' coercive policies.