A war without direct fighting

The Cold War was a period of tension and hostility between two superpowers — the USA and the USSR — and the rival blocs they led. It was "cold" because the two never fought each other directly. This unit covers the period 1945 to 1972.

Instead the rivalry played out through:

• a race to build nuclear weapons (the arms race);
• a battle for influence over other countries (aid, alliances, control of Europe);
• propaganda, spying and the threat of force.

Misconception alert: the Cold War never became a direct US–USSR shooting war. The danger was that a crisis (like Cuba in 1962) could escalate into nuclear war — but direct fighting between the two superpowers was always avoided.

Two ways of running the world

The deepest cause of the Cold War was a clash of ideologies — completely opposed ideas about how society should work.

Each side genuinely believed the other threatened its way of life — the USA feared the spread of communism; the USSR feared being encircled by capitalist enemies.

Whose idea?

Tehran, Yalta and Potsdam

During WWII the Grand Alliance (USA, USSR, Britain) met to plan the peace. The three conferences show relations cooling as the war ended:

• Tehran, 1943 — Roosevelt, Churchill and Stalin agreed the Allies would open a second front in France. Broadly friendly.
• Yalta, February 1945 — Roosevelt, Churchill and Stalin agreed Germany would be divided into zones; the USSR would enter the war on Japan; free elections were promised in liberated Europe; they agreed to set up the United Nations.
• Potsdam, July 1945 — held after Roosevelt's death and Germany's defeat. Truman (new US president) distrusted Stalin; Churchill was replaced mid-conference by Attlee. Disputes over reparations and the future of Poland showed the alliance breaking down.

Why Potsdam was tense: a new, tougher US president (Truman), the USA had just tested the atomic bomb, and Soviet troops already occupied Eastern Europe.

The bomb changes everything

In August 1945 the USA dropped atomic bombs on Hiroshima and Nagasaki, ending the war with Japan. This deepened suspicion between the superpowers:

• The USA had a terrifying new weapon — and had not told Stalin the details in advance.
• Stalin felt the bomb was partly aimed at intimidating the USSR, and pushed hard to build his own.
• The USSR tested its first atomic bomb in 1949, launching the arms race.

The bomb turned ordinary rivalry into something far more dangerous — from now on, a Cold War crisis could threaten the whole world.

Name the conference

The Iron Curtain and containment

By 1946 Stalin controlled much of Eastern Europe. In a famous speech at Fulton, March 1946, Churchill warned that an "Iron Curtain" had descended across Europe, dividing the free West from the communist East.

The USA answered with a policy of containment — stopping communism spreading further:

• Truman Doctrine (1947) — the USA would give money and support to any country threatened by communism (starting with Greece and Turkey).
• Marshall Plan (1947) — around $13 billion of US aid to rebuild Western Europe, so that poverty would not push people towards communism.

Stalin saw the Marshall Plan as "dollar imperialism" — a US bid to buy influence — and banned Eastern European states from taking part. He set up Cominform (1947) and later Comecon (1949) to bind the Eastern bloc to Moscow.

Two halves of one policy

The Berlin Blockade and Airlift

Germany — and its capital Berlin — had been split into four zones. Berlin sat deep inside the Soviet zone. When the Western Allies merged their zones and introduced a new currency, Stalin acted.

• June 1948 — Stalin blockaded all road, rail and canal routes into West Berlin, hoping to force the West out.
• The West responded with the Berlin Airlift — flying in food and fuel for nearly 11 months.
• May 1949 — Stalin lifted the blockade. It was a major propaganda victory for the West.

NATO and the Warsaw Pact

Berlin convinced both sides to form military alliances. Europe hardened into two armed camps:

NATO was formed in 1949; the Warsaw Pact in 1955, directly after West Germany was allowed to join NATO. The two blocs would face each other for the rest of the Cold War.

When was NATO founded?

The nuclear arms race

Each superpower raced to out-arm the other, building ever more powerful nuclear weapons:

• 1945 — USA has the atomic bomb; 1949 — the USSR catches up.
• 1952 (USA) and 1953 (USSR) — both build the far more powerful hydrogen bomb (H-bomb).
• By the 1960s both had long-range missiles able to strike each other's homeland.

MAD is a key idea: the sheer horror of nuclear war actually helped prevent direct war between the superpowers — a "balance of terror".

The race into space

Space was another arena of competition — proof of which system was more advanced, and closely tied to missile technology.

Sputnik (1957) shocked the USA: if the USSR could put a satellite in orbit, it could deliver a nuclear warhead anywhere. The space race and arms race were two sides of the same rivalry.

First into orbit

The Hungarian Uprising

Stalin died in 1953. When Khrushchev hinted at "de-Stalinisation", Eastern Europe hoped for freedom. In 1956 Hungary rose up under Imre Nagy, who announced free elections and that Hungary would leave the Warsaw Pact.

• The USSR sent in tanks in November 1956, crushing the uprising; thousands were killed and Nagy was later executed.
• The West protested but did not intervene — it would not risk war over the Soviet sphere.

Hungary showed the limits of Soviet control (people would resist) — but also the limits of Western "roll-back": containment meant stopping communism spreading, not fighting to free the East.

The Berlin Wall goes up

Through the 1950s and early 1960s millions of East Germans fled to the prosperous West through Berlin — an embarrassment for the communist East and a "brain drain" of skilled workers.

• In August 1961, overnight, the East built the Berlin Wall, sealing off West Berlin.
• Families were divided; those who tried to cross could be shot.
• The Wall became the great symbol of the divided Cold War world.

President Kennedy accepted the Wall rather than fight over it. In 1963 he visited West Berlin and declared "Ich bin ein Berliner" ("I am a Berliner") in solidarity with its people.

The Cuban Missile Crisis

The closest the world came to nuclear war. Communist Cuba, led by Castro, lay just 90 miles from the USA. After the failed US-backed Bay of Pigs invasion in 1961, Cuba turned to the USSR. In October 1962 US spy planes photographed Soviet nuclear missile sites being built there.

• Kennedy set up a naval "quarantine" (blockade) of Cuba and demanded the missiles be removed.
• After 13 tense days, Khrushchev agreed to withdraw the missiles; in return the USA promised not to invade Cuba and secretly removed its missiles from Turkey.

Consequence: the terrifying near-miss led to a "hotline" between Washington and Moscow (1963) and the Test Ban Treaty (1963) — the first steps on the road to easing tension.

How Cuba ended

The Prague Spring

In 1968 the reformer Alexander Dubček tried to create "socialism with a human face" in Czechoslovakia — loosening censorship and allowing more freedom. This became known as the Prague Spring.

• In August 1968 the USSR and Warsaw Pact troops invaded and ended the reforms.
• Afterwards the Brezhnev Doctrine declared the USSR would intervene in any Warsaw Pact country that threatened communism.

Like Hungary in 1956, Czechoslovakia showed the USSR would use force to keep control of its bloc — and that the West would not fight to stop it.

Event ↔ significance

Tap an event on the left, then tap its significance on the right.

Towards détente

After the fright of Cuba, both sides began to move towards détente — a deliberate relaxation of tension between the superpowers.

• 1963 — the "hotline" and the Test Ban Treaty (banning above-ground nuclear tests) eased the danger.
• 1968 — the Nuclear Non-Proliferation Treaty tried to limit the spread of nuclear weapons.
• 1972 — SALT I was signed by Nixon and Brezhnev, limiting the number of nuclear missiles each side could have. This is the end point of the unit.

Name the treaty

Who led each side?

Knowing the key leaders helps you keep the story straight from 1945 to 1972:

Watch the pairs: Kennedy faced Khrushchev over Berlin and Cuba; Nixon and Brezhnev signed SALT I in 1972.

The Prague Spring

Timeline: 1945 → 1972

Put the events in order

Tap the events in the correct time order, from earliest to latest.

Name the person

Sources and interpretations

In the AQA exam you handle sources and interpretations about this period. Two quick habits win marks:

• Ask who made it and why (provenance). A US poster and a Soviet cartoon about the same event will disagree — because each side used propaganda to win the "war of ideas".
• Use your own knowledge to judge it. Support or challenge a source with facts you know (dates, events, motives).

Interpretations differ: some historians blame the USA for the Cold War, some blame the USSR, and some blame mutual misunderstanding. Being aware that interpretations vary — and why — is exactly what the exam rewards.

Thinking like a historian

Why did tension begin to ease by 1972?

No single cause — but a chain of pressures, driven above all by the shock of Cuba and the huge cost and danger of the arms race:

The near-catastrophe of Cuba, the terrifying cost and risk of the arms race, and a wish to control nuclear weapons pushed Nixon and Brezhnev towards SALT I in 1972 — where this unit ends.

The essentials to remember

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