Nationalism is probably the dominant political ideology in today’s world, and is deeply institutionalized in the structure of the states system. At the same time, globalisation, Europeanisation and sub-state regionalisation are important developments that raise questions regarding the continued link between the state and the nation within a world in which the state’s system of sovereign control is weakened. One central question is whether a transformation of near-revolutionary proportions can be adequately captured within the nationalist framework. To this end I focus on Neil MacCormick’s position because he argues that liberal nationalism remains apt for such a changed context. This brings into focus assumptions about the role of the state and its attendant pre-suppositions of sovereignty – legal and political. Will salvaging nationalism promote the development of the post-sovereign constellation in today’s Europe? Or does it require a different perspective not only on allegiance but also on its attendant political organisation? This requires us to focus on the character of the European construct, and whether there are modes of allegiance that not only serve as real alternatives to the national and nationalism, but also capture the distinct features of the European Union as a post-sovereign constellation. In this paper I discuss whether federalism might serve that end. Does it work better than nationalism to capture the distinct traits of Europe’s development and does it provide a more persuasive normative framework for guiding Europe’s further constitutional development?