Who was to Blame for the Cold War?

• Capitalism (USA) vs Communism (USSR) — two totally opposed ideologies that were only allies "of convenience" during WWII
• The Grand Alliance broke down after Germany's defeat in 1945 — nothing left to hold the USA and USSR together
• Yalta (Feb 1945) went smoothly; Potsdam (Jul–Aug 1945) was tense — new leaders, the atomic bomb, and mistrust changed everything
• The atomic bomb (Hiroshima & Nagasaki, Aug 1945) terrified and angered Stalin, accelerating the arms race
• The Long Telegram (Kennan) and Novikov Telegram show both sides secretly believed the other wanted their destruction
• Churchill's "Iron Curtain" speech (March 1946) publicly declared the divide between East and West
• Stalin turned Eastern Europe into "satellite states" (Poland, Hungary, Romania, Bulgaria, Czechoslovakia, East Germany) as a buffer zone
• Truman Doctrine (1947) — the USA would help any country resist communism; ended US isolationism
• Marshall Plan (1947) — $13 billion in US economic aid to rebuild Western Europe and stop the appeal of communism
• The Berlin Blockade (1948–49) — Stalin's attempt to starve the West out of Berlin, defeated by the Berlin Airlift
• Consequences: NATO (1949), the Warsaw Pact (1955), and a permanently divided Germany (East/West)
• Orthodox historians blame Stalin; Revisionist historians blame the USA — there is no single "correct" answer

Here's the core problem in plain English: imagine two people who fundamentally disagree about how the world should be run — one believes everyone should own their own business and property (capitalism), the other believes the state should own everything so wealth is shared fairly (communism). Now imagine forcing them to be best friends and work together only because they have a mutual enemy trying to kill them both. That's the USA and USSR in World War II. The moment the enemy (Nazi Germany) was gone, there was no reason left for the friendship to survive.

Capitalism — the ideology where individuals can own property and businesses to make money. By 1941 the main capitalist powers were the USA (led by Franklin D. Roosevelt) and Britain. Roosevelt was fairly tolerant of Stalin and the USSR — he wanted to keep the peace.

Communism — the ideology where the state owns all property so everyone gets a fair share. By 1941 the USSR, led by Joseph Stalin, was the main communist power. Stalin's own domestic policies (forced collectivisation and rapid industrialisation) had already killed millions of his own people in the 1930s — which is exactly why the West was deeply suspicious of him even before the Cold War started.