This article asks whether there is a moral right to national self-determination. The partiality argument as a basis for discussing the moral right to self-determination confuses nation and nationalism and is found wanting. Social science conclusions on the construction of nations have to be brought into the framework of the ethical argument, because they reflect upon the nature of the 'self' in question. While a case can be made that national secession is sometimes beneficial, it cannot be agreed that there is a general moral right of national self-determination. The 'self' in question is too arbitrary, and the process by which nations are created and defended involves high risk of violent conflict. Both Kantian and consequentialist ethics must therefore reject the idea of a general right of self-determination. The key moral problems arise over the enterprise of the creation of a state, which is the core of the nationalist project. Those difficulties are a central reason for the moral ambiguity of nationalism.