The USA and the USSR emerged as the superpowers after the world war II.
→ Their rivalry for the dominance over the world politics was the main cause of the 'cold war'.
→ There was also ideological conflict between communism advocated by the USSR and capitalism practised by the western democracies.
→ The USSR had brought Eastern Europe under its control and there was threat of the spread of communism and the Soviet expansion in Western Europe. This led to the formation of the North Atlantic Treaty Organisation (NATO) by the USA and its allies in Europe.
→ The Communist Revolution took place in China. This was threat to the allies of the USA in South-East Asia. This led to the formation of the South-East Asia Treaty Organisation (SEATO).
→The USSR was looking forward to dominate Central Asia. Therefore, the USA and its allies formed Central East-North Treaty Organisation (CENTO).
→ In response to the formation of the military alliances by the USA, the USSR and its allies formed Warsaw Treaty Organisation.
→ These two powergroups and military alliances tried to win over to their side the rest of the countries in the world.
→ There was atmosphere of mutual suspicion and fear, leading to the race for nuclear armaments. Till 1949, the USA was the only nuclear power. The USSR acquired nuclear capabilities in 1949.