Key topic 4 · Three crises: Berlin, Cuba and Czechoslovakia

What a Grade 9 answer knows here. All three crises were resolved by the same unspoken rule — each superpower may do what it likes inside its own sphere and neither will fight over it. Détente is not a change of heart afterwards; it is that rule being written down.

Every lesson here ends the same way: learn it, teach it to an AI pupil who asks the awkward question, then defend it against the thinker with the strongest claim on it — free · no account needed.

3 lessons, each answering one essential question with the story, the dates that earn marks, the people to place, how historians disagree and the cap in the mark scheme that bites. Completely free.

The 3 lessons

The U2 incident and the Berlin Wall

Why did the West protest about the Wall and do nothing, and what does that tell us? American U2 aircraft had been photographing Soviet territory from around 21,000 metres since 1956, above the reach of Soviet interceptors.

Examined through causation and consequence. Learn the U2 incident and the Berlin Wall →

The Bay of Pigs and the Cuban Missile Crisis

If the crisis ended in a trade, why was it presented as a Soviet climbdown? Castro took power in January 1959 and nationalised American-owned sugar, oil and utilities.

Examined through causation and consequence. Learn the Bay of Pigs and the Cuban Missile Crisis →

Czechoslovakia 1968 and the Brezhnev Doctrine

Why was Dubček invaded when, unlike Nagy, he never proposed leaving the Warsaw Pact? Czechoslovakia had been the most industrialised country in the bloc and its economy was stagnating under central planning; it had also had the harshest de-Stalinisation record, with Novotný in place since 1953 and no rehabilitation of the…

Examined through causation and consequence. Learn Czechoslovakia 1968 and the Brezhnev Doctrine →

The dates that earn marks in this key topic

Two from each lesson, in the order the topic is taught — each with the reason it is worth a mark, and the lesson that places it.

1 May 1960 — Powers shot down near Sverdlovsk two weeks before the Paris summit.: The timing is what makes the incident consequential rather than embarrassing. (The U2 incident and the Berlin Wall)
16 May 1960 — The Paris summit collapses.: The thaw ends and Berlin is left unresolved for a new administration. (The U2 incident and the Berlin Wall)
April 1961 — The Bay of Pigs fails.: It produced the Soviet-Cuban military relationship and Khrushchev's estimate of Kennedy. (The Bay of Pigs and the Cuban Missile Crisis)
16 October 1962 — The photographs reach Kennedy; ExComm convenes.: The crisis begins with intelligence rather than with a threat, which is why there was time to deliberate. (The Bay of Pigs and the Cuban Missile Crisis)
January 1968 — Dubček replaces Novotný.: Reform begins inside the Party, by the Party, which is what makes the case different from Hungary. (Czechoslovakia 1968 and the Brezhnev Doctrine)
April–June 1968 — The Action Programme; censorship abolished; the Two Thousand Words manifesto.: The specific measures Moscow objected to, none of which concerned the Pact. (Czechoslovakia 1968 and the Brezhnev Doctrine)

The people to place

Francis Gary Powers — U2 pilot; survived, was tried in Moscow, and was exchanged in 1962. (The U2 incident and the Berlin Wall)
Dwight Eisenhower — Accepted personal responsibility rather than apologise, and lost the summit and his Moscow visit. (The U2 incident and the Berlin Wall)
Walter Ulbricht — GDR leader who pressed for the closure and had told a press conference in June 1961 that nobody intended to build a wall. (The U2 incident and the Berlin Wall)
John F. Kennedy — Defined the three essentials in July, protested in August, and privately preferred a wall to a war. (The U2 incident and the Berlin Wall)
Nikita Khrushchev — Deployed and withdrew; obtained the non-invasion pledge and the Jupiters and could not say so. (The Bay of Pigs and the Cuban Missile Crisis)
Robert Kennedy — Conveyed the Jupiter undertaking to Dobrynin with the condition that it never be revealed. (The Bay of Pigs and the Cuban Missile Crisis)
Vasili Arkhipov — The Soviet submarine officer whose refusal prevented the launch of a nuclear torpedo on 27 October. (The Bay of Pigs and the Cuban Missile Crisis)
Alexander Dubček — Led the Prague Spring, ordered no resistance, signed the Moscow Protocol and was removed in 1969. (Czechoslovakia 1968 and the Brezhnev Doctrine)
Leonid Brezhnev — Authorised the invasion and stated the doctrine in November 1968. (Czechoslovakia 1968 and the Brezhnev Doctrine)
Gustáv Husák — Replaced Dubček and directed normalisation. (Czechoslovakia 1968 and the Brezhnev Doctrine)
Jan Palach — Student who burned himself to death in Wenceslas Square in January 1969. (Czechoslovakia 1968 and the Brezhnev Doctrine)

What students say — and what is actually the case

“The Wall was built to stop Westerners entering East Berlin.” — It was built to stop East Germans leaving. Around 2.7 million had gone, disproportionately young and skilled, and the state could not function without them. (The U2 incident and the Berlin Wall)
“Khrushchev backed down and got nothing.” — He obtained a public non-invasion pledge and the private removal of the Jupiters, both of which were delivered. The appearance of a climbdown was the price of the second, and Kennedy needed the secrecy more than Khrushchev did. (The Bay of Pigs and the Cuban Missile Crisis)
“Dubček wanted to end communism in Czechoslovakia.” — He was a lifelong communist reforming the Party from inside it, and repeatedly confirmed Warsaw Pact membership. That is exactly what makes the invasion significant. (Czechoslovakia 1968 and the Brezhnev Doctrine)

What the specification asks for

The clauses of 4HI1 this key topic examines, one per lesson. Incandio is aligned to the specification and is not published by Pearson.

“The U2 incident (1960) and its effects on the Paris Summit Conference. Reasons for the construction of the Berlin Wall in 1961, including the refugee problem. The effects of the Berlin Wall on relations between East and West Germany and between the Superpowers.” — The U2 incident and the Berlin Wall
“The Bay of Pigs invasion, the causes and key events of the Cuban Missile Crisis and the reasons for its outcome” — The Bay of Pigs and the Cuban Missile Crisis
“The Soviet invasion of Czechoslovakia – its causes, events and impact, including the Brezhnev Doctrine” — Czechoslovakia 1968 and the Brezhnev Doctrine

Then teach it, and defend it

Every lesson above ends the same way: you explain the argument to Ember, an AI pupil who asks the awkward question, and defend it in a structured debate marked against published descriptors.

All of A world divided: superpower relations, 1943–72 · Incandio History · The 4HI1 specification