Both USA and USSR contributed to the slow evolvement of the Cold War, although I would accuse the USSR of being the more responsible of the two parties. Stalin's initial paranoid suspicions of the West gave him the need to cripple Germany to feel protected against future threats, and I believe that he used this excuse to too far an extent, thus bringing about the Cold War. During the years of 1945 and 1947, he tightened his grip over the countries of Eastern Europe that the red army had entered during the last year of the war. This was achieved in the way that coalition governments were set up that consisted of both Communist and democratic parties, but the key posts tended to be held by Communists. "Free" elections followed which resulted in communist governments replacing the coalitions, but the methods used to win the elections were based around intimidation and arrest of non-Communists.
             Winston Churchill introduced a well-known quote regarding these Russian tactics in 1946 at Missouri, USA; "From Stettin on the Baltic to Trieste on the Adriatic, an iron curtain has descended." In my opinion, this was the unofficial beginning of the Cold War. However, despite that fact that this statement was made containing the implication that the "iron curtain" was caused solely by the Russians, the USA also had a lot to do with its existence. Stalin's increased paranoia had been largely increased when the Americans successfully tested their atomic bomb at a desert site in the USA on 16th July 1945, and this would not doubt him an augmented belief in his firm need for buffer states surrounding Russia. Truman also refused to agree to act as harshly towards Germany as Stalin made clear he wanted at the Potsdam Conference in 1945, which too would have added to the pressure upon Stalin to act upon his suspicions.
             In 1947, America intervened in the conflict between the communists and the democratic parties in Greece and this marked the begin...