Results from the preceding project The Legitimacy of a European Constitution in View of the Conditions Created by National Traditions indicated that the EU finds legitimation above all in the benefit generated for the nation states as part of European level proceedings. In practice, this republican idea enforces a certain degree of solidarity among the member states. A European policy conceptualised or implemented independently of the member states interests does hardly exist. This is clearly evident from the EU budget, which primarily finances projects on member state level. It is much less a common idea, but rather the shared advantage which prompts the member states to seek integration. The failed referendums in the Netherlands and France have shown that this solidarity is increasingly being challenged. The unanimous welfare benefits were apparently not anymore appreciated as such by the majority of the respective peoples. This poses questions regarding the shape and extent of solidarity in Europe, questions which at the same time are central to the legitimacy of a unified Europe. The research in this second phase of the project will thus be oriented towards the following questions: Concerning the problem of legitimacy in a union based on the principle of national sovereignty, what forms of European solidarity and European social market economy are required or necessary? What forms of open or mandatory co-ordination of national policies on the transnational level are feasible in these policy areas, and under which conditions or by which mechanisms could these be legitimised? What limits exist with respect to solidarity and co-ordination of such kind, both systematically and pragmatically?