The article proposes to conjoin the analysis of European integration and a modern systems theory of society. At first identifying some deficiencies in current debates on governance and democracy in Europe, it then introduces some tenets of modern systems theory relevant for the argument, focusing on the notions of ‘world society’;, ‘structural coupling’, and ‘social evolution’;. Using the debate on an emerging European constitution as an example, it then demonstrates how a systems-theoretical perspective can help to resituate the account of a European constitutionalism in the overall evolution of world society's legal and political systems. In an equal fashion, it proposes to sharpen the theoretical discussion on democracy in Europe by first outlining the function of legitimacy in a functionally differentiated political system. A concluding section comments on the ‘value added’ of a modern systems-theoretical perspective which is still uncommon in European Studies and IR.