How and why did the Cold War develop, escalate and end between 1945 and 1991?
Analyse the origins, key crises, ideological conflict and eventual end of the Cold War between the United States and the Soviet Union from 1945 to 1991.
The origins, escalation, key crises and end of the Cold War between the United States and the Soviet Union, from the post-war division of Europe to the collapse of the USSR in 1991.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
You must explain the origins of the Cold War, its key crises and the way it was conducted, and assess why it ended. Strong answers engage with the debate over who was responsible for its origins and weigh the factors behind its peaceful conclusion.
Origins and the division of Europe (1945-1949)
The wartime alliance between the USA, USSR and Britain broke down after victory over Germany in 1945. At the Yalta and Potsdam conferences (1945) the Allies disagreed over the future of Eastern Europe, especially Poland. The Soviet Union, under Joseph Stalin, installed communist governments across the territories its army occupied, while the USA, under Harry Truman, sought open markets and democracy. Winston Churchill warned in 1947 that an "iron curtain" had descended across Europe.
The USA adopted containment: the Truman Doctrine (1947) promised support to nations resisting communism, and the Marshall Plan (1947-1948) offered economic aid to rebuild Western Europe. The Soviets responded with the Berlin Blockade (1948-1949), countered by the Western airlift, after which Germany was split into West and East (1949). Military blocs formed: NATO (1949) in the West and later the Warsaw Pact (1955) in the East. In Asia, the communist victory in China (1949) and the Korean War (1950-1953) globalised the conflict.
Escalation and crises (1949-1969)
The Cold War was sustained by ideology and an arms race. Both sides built nuclear arsenals, producing the doctrine of mutually assured destruction, and competed in the space race after the Soviet launch of Sputnik (1957). Key crises brought the world close to war.
The Berlin Crisis culminated in the building of the Berlin Wall (1961), which stopped the flow of East Germans to the West and became the symbol of a divided Europe. The Cuban Missile Crisis (October 1962), triggered by Soviet missiles in Cuba, was the closest the superpowers came to nuclear war; it ended when Soviet leader Nikita Khrushchev withdrew the missiles in exchange for a US pledge not to invade Cuba and the quiet removal of US missiles from Turkey. The crisis prompted the first arms-control steps, including the 1963 Partial Test Ban Treaty.
Detente, the Second Cold War and proxy conflicts
The late 1960s and 1970s brought detente, a relaxation of tension marked by the SALT I treaty (1972) and President Nixon's visit to China (1972). Yet the conflict continued through proxy wars across the developing world, most destructively in Vietnam, where US intervention against communist forces ended in withdrawal (1973) and communist victory (1975). Detente collapsed after the Soviet invasion of Afghanistan (1979), ushering in a "Second Cold War". President Ronald Reagan increased defence spending, denounced the USSR, and announced the Strategic Defense Initiative (1983).
The end of the Cold War (1985-1991)
The Cold War ended faster than almost anyone predicted. Soviet leader Mikhail Gorbachev, taking power in 1985, faced a stagnant economy and an unaffordable arms race. His reforms, glasnost (openness) and perestroika (restructuring), and his decision not to use force to prop up Eastern European regimes, transformed the situation. Arms-control agreements such as the INF Treaty (1987) eased tension.
In 1989 communist governments fell across Eastern Europe, and the Berlin Wall was opened on 9 November 1989. Germany was reunified in 1990. Within the USSR, nationalist movements and a failed hardliner coup (August 1991) accelerated collapse, and the Soviet Union was formally dissolved in December 1991, leaving the USA the sole superpower.
Historians debate why it ended. Some credit Reagan's pressure and Western strength; others stress Gorbachev's choices, Soviet economic failure, the appeal of Western prosperity, and pressure from movements such as Solidarity in Poland. Most see a combination of long-term Soviet decline and Gorbachev's reformist decisions.