The article tries to ascertain whether the Eastern European countries, which formerly belonged to the oriental side of the Iron Curtain, and the Central European countries (Visegrád Group), could suppose a destabilizing structural element for the European Union. Besides, the article will study how the European Union uses, on the one hand, the European Neighbourhood Policy to carry out its interrelations and, on the other hand, the two-speed Europe in order to manage the integration in the communitarian policies. The lack of cohesion and confidence suffered among the EU members could be even more dangerous than any other external agent itself. The possibility of a threat for the European integrity, owing to the lack of implication and collaboration of the Visegrád Group in the EU's projects, will also be a subject of study along the article. Parallel that, it is evident that Russia has big interests in Europe and, in the era of Post-Cold War, it still influences the former eastern pro-soviet countries. The necessity of a sanitary cordon is a reality for those two actors, both Europe and Russia. Moreover, the eastern countries are directly affected by their geopolitical game and their international insecurities.