Even before the end of World War II, in which the United States and the Soviet Union had fought together as allies, there were signs of tension between the two nations. Once the hostilities were over, those tensions quickly grew to create what became known as a "Cold War" - a tense and dangerous rivalry that would cast its shadow over international affairs for decades. Both the United States and Soviet Union were responsible for the outbreak of the Cold War.
Many arguments can be posed to blame the United States for the Cold War. At Yalta, Roosevelt did not specifically define what he meant by a sphere of influence. Stalin interpreted it as total control over the East but the United States only wanted Russia to have an influence. The United States tested the atom bomb in 1945 which caused tensions between the two superpowers.
When Truman came into office, he was even more anti-Communist and suspicious of Stalin than his predecessors. The Truman Doctrine and Marshall Plan allowed America to send money and supplies to stop the spread of communism. This was deemed unfair in Stalin's eyes. In addition, the Berlin crisis in which American airlifted supplies to Berlin was seen by Stalin as a form of confrontation. Finally, NATO, an alliance of western European countries against communism, greatly upset Stalin.
Many arguments can also be posed to blame the Soviet Union for the Cold War. At Yalta, disagreement strained relationships. Stalin insisted that the Soviet Union border be moved into Poland despite American objection. The Soviet Union quickly took over countries that were free from German control. In addition, Stalin set up communist governments in these countries and in Poland. The United States saw the Cominform and Comecon, programs set up to...