After World War 2, USA and USSR unite in the victory of defeating Nazi Germany. Then the allied nations had a conflict on the different ideologies, Soviet Union was a Communist country, which was ruled by a dictator and put the needs of the state ahead of personal Roman rights.
September 2, 1945
Dictator Joseph Stalin
March 12, 1947
We will give money and military aid to countries threatened by communism, and effectively stop communists from taking control of Greece and Turkey.
USA and USSR have made atomic bombs that created a deterrence which means the action of discouraging an action or event through instilling doubt or fear of the consequences.