As the title of this lecture indicates, it builds upon the author s previous ananlysis of the European Communities market building efforts (C. Joerges, The Market Without the State? The "Economic Constitution" of the European Community and the Rebirth of Regulatory Politics , European Integration online Papers , Vol. 1, No. 19 ( http://eiop.or.at/eiop/texte/1997-019a.htm ). The analytical approach chosen includes a "comparative analysis" of legal and political science theories of European integration. It is a asserted, that the schisms between legal and political sciences inhibit an adequate understanding of the European Polity. Lawyers risk to overlook important institutional innovations; political scientists are urged to address the "constitutionalist" dimension of the European law. The theoretical argument is then substantiated by an analysis of the German Constitutional Court s decision on the Maastricht Treaty. Without even mentioning the normative visions of Germany s neo-liberal tradition, the Constitutional Court has, while pretending to defend the nation state, in fact endorsed the idea of a purely economic constitution of the European Community. The paper argues that the Europeanization process is de facto and de jure depending upon a constitutional vision which is to overcome the separation between "political" nation states and an "unpolitical" European governance structure.