Who was to blame for the Cold War? There are two possible verdicts; the USA and USSR. Both these sides had different beliefs, USA was a capitalist country while the USSR was a communist country, and this was one of the main causes of the cold war. I believe that both sides were almost equally responsible for the start of the Cold War but USA may be blamed slightly more than the USSR because as you will see there are more arguments against the USA. The arguments against the USA (that indicate that the USA was the one to blame) are many. At the Yalta conference, February 1945, towards the end of the 2nd World War, Roosevelt didn't define what he meant by Eastern Europe being seen as "A Soviet sphere of influence". Stalin seems to define it as a total control of the USSR over the East but the USA interprets it by saying that Russia would only have a slight influence. Roosevelt also showed lack of trust in Stalin, as we can see at sources 6 and 8. An other mistake of Roosevelt was that he allowed Russia to move border into Poland as long as Russia didn't interfere with Greece. This clearly shows how the USA wanted to prevent the wide spreading of communism in Europe. The fact that America tested the atomic bomb in 1945 caused tension between the two countries and caused the USSR to fear even more the USA. After Roosevelt died, Truman became the president of the USA.