The United States of America (USA) and the Union of Socialist Soviet Republics (USSR) had very different political and economic beliefs. After World War Two, the USA and the USSR became superpowers. The two superpowers were governed very differently.
The USA is a capitalist society:
The USSR was a communist society:
Winston Churchill, the wartime Prime Minister of Britain described the ideological divide between the capitalist West and the communist East, by commenting that an 'Iron Curtain' had descended over Eastern Europe.