Vlad Perju (Boston College - Law School) has posted Dual Sovereignty in Europe? A Critique of Habermas's Defense of the Nation-State on SSRN. Here is the abstract:
Jürgen Habermas’s influential account of the transnationalization of democracy is typically seen as a bold attempt to articulate the political-philosophical foundations of European integration. Habermas posits an identity split between individuals as citizens of their nation states and (the same) individuals as members of the future European Union. According to the dual sovereignty thesis, nation states and the EU are co-original and co-determinate.
I challenge this conception on two grounds. First, split identity is a source of fragmentation that subverts the transnationalization of democracy. It would be irrational for EU citizens to partake in a project that empowers states to undermine European unification. Second, Habermas misinterprets European constitutional doctrine. The doctrines and practice of European constitutionalism do not provide support for the dual sovereignty thesis. In reality, European constitutionalism calls for a bolder jurisprudential account of European unification than Habermas’s concern with preserving the role of constitutional nation-states can provide.