On April 20, 2016 the NATO-Russia Council meeting took place. This meeting was necessary because of the continuous offensive policies of Russia (mainly in Ukraine), but also because of the increasing tension along Eastern borders of the Atlantic Alliance. The Russian growing naval engagement in the Baltic region and in the Black Sea has caused NATO reaction, which has significantly increased its presence in the Eastern borders during the last year. For this reason, NATO and Russia strongly requested a Council meeting on April 20 in Brussels. The aim of this meeting was to both discuss the Ukrainian issue concerning the illegal annexation by Russia of the Crimea, and transparency between the two parties in order to reduce the risk of a conflict. Since 2010, NATO has put in place a new strategy based on collective security, conflict prevention and cooperation with neighbours countries in order to neutralize any type of threat for its member countries. This article initially will examine the post-Cold War NATO’s key strategies, stressing out its « new » principles to deal with the threats of a multipolar world. Then, we will examine NATO reactions against the offensive policy of Russia and the conclusions of the meeting of 20 April. Finally, we will consider NATO policies founded on the increasing military presence along the Eastern border of the Alliance, highlighting the current political-military situation based on the concept of “action-reaction”.