The supranational body of the European Union also has it own executive, legislative, and judicial supranational institutions. The European Parliament performs legislative functions as it reviews and approves decisions made by the Commission. Executive functions are shared by the Commission, the Council of Ministers and the European Council. While judicial function is given to the European Court of Justice, whose function is similar to that of the Supreme Court of the United States of America. Aside from these institutions, the ambitious Maastricht Treaty established three pillars for the European Union: a common currency (the Euro), a common foreign and security policy, and a common justice and internal policy. (Ray, 375-376) In a sense, the EU accomplished a feat like that of a nation-state.
At present, the European Union is composed of twenty-five member nations. There were five original members in 1957. They are: Belgium, Germany (the east would become part in 1991), France, Luxembourg, and the Netherlands. By 1993, the number was already twelve with: Denmark, Ireland, United Kingdom, Greece, Italy, Portugal, and Spain. Austria, Finland, and Sweden joined the EU on January 1, 1995. The latest additions to the EU were Cyprus (Greek part), the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia in 2004.
It seems that the neo-functionalist approach for economic, political and cultural integration for Europe worked well as seen in the influx of membership in the EU. In fact, neo-functionalists predicted this "spillover" of integral growth because it is one of the central features of the theory. However, because of the dynamics of changing economic and political interests and environment, the theory is put to the test or, to put it more aptly, the theory and practice evolves.
To discuss the challenges to the European integration, there is a need to go back to the fundamentals of neo-functionalism according to E.B. Haas (1958). First of the features is that neo-functionalism focuses on the process. Haas posits: "…integration is the process whereby political actors in several distinct national settings are persuaded to shift their loyalties, expectations and political activities toward a new centre, whose institutions possess or demand jurisdiction over the pre-existing national states…' (1958:16)
Bear in mind that integration is not only concerned with the institutional and structural aspects of the society, but also the integration of values, "loyalties", and "expectations." The question now is, in the light of disparities of economic conditions and political loyalties still existing within the member-states of EU, how can the Union maintain itself without sacrificing sovereignty in the still-independent states?