The Treaty of Accession and Differentiation in the EU

Abstract

With the entering into force of the Accession Treaty, on 1 May 2004, the process of European integration has entered a new phase. The EU of 25 will differ from the EU 15 in many ways.
First, the accession of 10 new Member States has fundamentally changed the institutional framework and decision-making capacity of the Union. Reaching agreement with 25 Member States is obviously much more difficult than with 15. It remains to be seen how the Nice arrangement for QMV will affect the EU’s decision-making in practice awaiting the entry into force of the Constitution.
Second, EU enlargement raises the question of balance in the EU. On the one hand, there is a question of balance between Member States: big and small, old and new, countries defending a more intergovernmental and supranational view on European integration. On the other hand, there is the traditional issue of balance between the institutions and in particular the institutional triangle constituted by the Commission, the Council and the European Parliament. The discussions surrounding the inauguration of the Barroso Commission clearly revealed the importance of this institutional balance and the power relations between the institutions.
Third, and this is the central topic of today’s conference, EU enlargement raises questions about the future functioning of the Union and the application of the acquis communautaire. Under the Accession Treaty, the 10 new Member States will not automatically apply the entire acquis nor will they be able to participate in all areas of EU activity on a par with the old Member States. In other words, the Accession Treaty provides for differentiation between the old and new Member States during the first years after enlargement. After a short introduction on the legal basis and structure of the Accession Treaty, this paper essentially tries to discuss the instruments of differentiation and their consequences for the future functioning of the Union.