In this article, I propose to examine the issue that at present most mobilizes the European states and public opinion within them: the modification of the institutional-political model, in the form of a Constitutional Treaty for Europe, requiring parliamentary or popular ratification by its twenty-five member States, within a period that remains undecided. Events surrounding the consultation proposed to the European governments and their citizens, indicate -particularly if we take into account the negative votes in France and Holland, and others that may yet occur -that the European Union is divided, raising the concern that its process of regional integration could suffer interruption or even reversal. My analysis of the reasons European citizens and European states find themselves divided, with emphasis on those that separate the bureaucracy in Brussels from the EU's citizens and national governments, will revolve on two basic axes: the enlargement of the EU, recently grown from fifteen states to twenty-five, and the transformation of the EU's political-institutional model, which in securing itself to a constitutional anchor modifies both symbolically and substantively the degrees of sovereignty and autonomy of Europe's numerous political actors. So doing, this analysis will seek support in theoretical currents that, stimulated by the importance and singularity of the process of European construction, have been brought to bear on the examination of the political instruments and procedures involved, their determinants, and their consequences. Beginning with the matter of enlargement, this article will look at the recurrent problems arising from admission of the ten new member countries from the Center and East of the continent -that is, the "other Europe" -formally incorporated in May 2004, and at the decisive weight this had in the decision to formulate a Constitution for Europe. Arriving thus at my second topic, I will reconstruct the debate between a "Europe-Union of States" and a "Super-State Europe," discussing issues directly connected to this classic dichotomy -democracy, legitimacy, formation of a collective identity, division of sovereignty, and others -which, having direct impact on European citizens, will determine the acceptance or rejection of what is being proposed to them in the Constitutional Treaty.