To what extent were soviet policies responsible for the outbreak and development of the cold war between 1945, 1949?

The orthodox school sees the Cold War as the product of the aggressive and expansionist foreign policies of USSR. This view has been presented by historians such as W. H .McNeill, H. Feis, and A. Schlesinger. After WW2 a power vacuum was left in a large part of central and Eastern Europe. Stalin took the advantage of this in order to strengthen the Soviet Union and spread communism. In the Yalta conference (Feb 1945), Stalin demanded …

…Soviet point of view, most of Stalin's actions were offensive towards the West Alliance in the US point of view. The conflict's outbreak was in part a consequence of the Western powers' failure to accommodate Soviet security needs, but this very failure stemmed from Soviet policies. Stalin's policies were too aggressive in the West point of view, and were unacceptable. Thus the Soviet foreign policies were quite responsible for the outbreak of the Cold War.