With the end of the Cold War, the former subjects of the Soviet Union re-entered to political, cultural and economic arena starting a new phase in European continent and in European Union by the enlargement process. However the extending of European Union eastwards gave rise to the debates over the boundaries of Europe and the uncertainty about the final limits are becoming a problematic field that effects the future of the Union.
According to Smith, the notion of 'boundary' implies "a disjunction between an entity (the EU) and its environment", that is a break between two independent systems. Smith defines four types of boundaries which are geopolitical , institutional/legal, transactional, and cultural/political (Smith, 1996: 13). Even though the fact that this four categories of boundaries formulated by Smith are sometimes overlapping, they may be useful to analyze conceptualization of boundaries across Europe.
"The geopolitical boundary refers to the fact that geopolitics produces a dividing line between insiders and outsiders."
The first boundary line between the EU and the outside is produced by geopolitics (Smith 1996) Geo-political enlargements have been a strategic issue for the European project since its very beginning. However, the EU enlargement eastwards radically differs from previous experiences because of either the number, variety and complexity of the interior issues of the countries involved, or the exceptional international circumstances in which it occurs. Due to the "withering away" of their past fifty-years long socialist constitutional asset, Eastern European countries not only raise altogether new questions, that are specific to the area. They raise also problems and expectations concerning the new position of the EU as a significant geo-political "player" in the world system arena. Since this geopolitical boundary is mainly determined by the international system as such, the EU has limited control over it.