The European Union undoubtedly is one of the most significant and cohesive political-economic complexes in contemporary world. The European Union phenomenon could be interpreted as “Unity in Variety “based on the fact that this integrated community bears fragmentation and centrifugal inclinations and presents a various collection of political, social and cultural units.
During half a century of existence, the European Union has been influenced by different trends and waves. These trends could be categorized at three different levels: The domestic level (national level within member states), regional level (the European level) and international level (world system). The current European Union is in fact a product of these three forces. Aiming at understanding the status of the European Union, its future role and its integration process, we need to emphasize the most important domestic and regional challenges and obstacles in front of it as well as international trends and players affecting this union.
The present article aims to introduce the most important challenges of the European Union in domestic level and the role and influence of the United States on integration process of this union. Finally a more obvious image of the status of the EU and its prospect in international system will be achieved.