Washington's continued aggressive approach to boost its geopolitical and geostrategic advantages over Russia through NATO's eastward expansion and European anti missile system was a clear proof to Moscow that the strategic balance is changing in favor of USA and at the same time its strategic vulnerability is increasing. Simultaneity of these developments with a positive perception in Moscow of possibility of realizing the idea of “great power” has encouraged Russia to try to balance more with United States. This situation with an increase in the feeling of decline in relative security in both sides has enhanced “uncertainly” then “security dilemma” between them. Disruption in the bilateral arms control is one of its consequences. In spite of the fact that START-3 treaty’s entry into force increased hope to solve "the security dilemma”, remaining the atmosphere of Mistrust indicates that the agreements are fragile.