The Soviets desire to establish their “sphere of influence” in Eastern Europe and disagreement with the U.S. over the fate of Germany was another reason. The U.S. retaliated by issuing the Truman Doctrine in 1947 that authorized U.S. aid to anti-Communist forces in countries threatened by Communists. The Soviet testing of the atomic bomb in 1949 and its tacit approval of a North Korean attack on South Korea that led to the Korean War further soured relations between the two nations. The Vietnam War in which the U.S. intervened militarily to prevent a Communist take-over of the country was another area of conflict between the U.S. And the Soviet Union.
Containment.” (2006). Nuclear Files.org: Nuclear Age Peace Foundation. Retrieved on November 18, 2006 at http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/history/cold-war/strategy/strategy-containment.htm
Bell, P.M.H. (2001). The World since 1945 — An International History. London: Oxford University Press Inc.
The U.S. represented democracy, individual liberty and capitalism, while the U.S.S.R. was the first Marxist state committed to a command economy and the spread of the communist revolution around the world.