In this paper, I consider the objection that unilateral secession by a national group (e.g., the Scots) from a legitimate, nonusurping state would wrong minority nationalities within the seceding territory. I show first that most proponents of this objection assume that the ground of the right to national self-determination is the protection of the group’s culture. I show that there are alternative justifications available. I then set out a version of this objection that does not rely on this claim; on (...) this objection, a national minority that seceded and created its own state would commit an expressive wrong against minorities within the territory over which it claimed jurisdiction. I show that this objection is undermotivated: only under a specific set of circumstances would the minorities of the secessionist region be subject to an expressive wrong. Finally, I show that the correct way to think about the claims of minorities in secessionist regions is in terms of a claim to secure access to equal civic status such that they are not at risk of becoming justifiably alienated from their new state. If a secessionist group cannot provide this guarantee to the minority residents of their territory, then their seceding would commit wrongful harm, and the presumption in favour of collective autonomy is defeated. I call this defeater the ‘Alienation Defeater.’With this in hand, we are now in a position to explain why nations are normatively special. Responding to the objections broached by Allen Buchanan and others, I show that even if other kinds of groups, such as religious groups, have the features in virtue of which nations have a claim to self-determination, this does not entail that those groups also have the right to secede. This is because an account of self-determination needs a list of ‘defeaters’—features in virtue of which a group’s claim to self-determination is defeated. I argue that religious groups are the strongest candidate for having a claim to collective autonomy in virtue of sharing many features with nations. I then argue that religious groups will run afoul of the Alienation Defeater; religious identity is too narrow to be the basis of the dominant collective identity of a state. This does not apply to nationality. This, I explain, is because of qualitative differences between religious groups, qua religious groups, and nations. (shrink)