One of the most important issues surrounding the new Constitutional Treaty is the extent to which it will be able to generate a greater popular identification with the European integration project. This article explores this issue in more depth by looking at the role of popular identification in securing polity legitimacy in general. An argument is then developed that although popular identification and polity legitimacy are often separated, from a practical point of view, it is preferable to think of polity legitimacy in such a way as to incorporate questions of identity and affectivity. The article then outlines a way in which such a theory can be constructed, termed an 'aesthetic' theory of political legitimacy. Such a theory is then applied to understand both the EU as a distinctive type of post-state polity and the role that the constitutional tradition might play in securing its legitimacy.