States already exercise the right of admittance or exclusion. Nonetheless, it is the task of political philosophy to determine whether they should. Historically, the state has been an exoskeleton whose purpose was to protect and promote the development of free and national societies. However, pressing phenomena such as globalization, migration and international integration are pushing for a paradigm shift in the state’s raison d’être in this regard. For what used to be a strong exoskeleton is now an internal one, diminished in visibility and weakened in character. And this raises some questions regarding two fundamental aspects of all democratic states. Namely, that the demos is bound; and that this demos has the right to define, and exercise control over, its own boundaries. This essay attempts to respond to the challenge the latter encounters today. And it seeks to do so from a normative perspective, rather than a positivist one, assessing one aspect of an argument that defends the morality of a state’s decision to unilaterally close its borders: David Miller’s self-determination account as a basis for territorial jurisdiction.