The Cold War was the long period of tension between the USA and the Soviet Union after 1945. Its causes can be divided into long-term differences and short-term events.

Long-term: Clashing Ideologies

The deepest cause was a clash of beliefs going back to 1917. America was capitalist and democratic; the Soviet Union was communist, a one-party state that controlled the economy. Each side genuinely believed the other system threatened its way of life.

Short-term: Wartime Tensions

Their wartime alliance was one of convenience against a common enemy. At the Yalta and Potsdam conferences (1945), cracks appeared over the future of Germany and the fate of Poland. Stalin wanted a buffer of friendly states; the West saw this as aggressive expansion.

The Iron Curtain

Stalin installed communist governments across Eastern Europe, and in 1946 Churchill declared that an "Iron Curtain" had descended across the continent. The USA, fearing the spread of communism, launched the Truman Doctrine (promising help to countries resisting communism) and the Marshall Plan (economic aid to rebuild Western Europe).

Why "Cold"?

Mutual suspicion, the atomic bomb and events like the Berlin Blockade deepened the divide. Yet the superpowers never fought each other directly, because the risk of nuclear war was too terrible — which is why it is called a "cold" war. Historians still debate which side was most to blame.

Year 9 Democracy and Dictatorship

The Causes of the Cold War