Superpower Relations and the Cold War, 1941-91: The Grand Alliance and the Wartime Conferences, 1941-45
The Grand Alliance was the wartime partnership between the USA, the USSR and Britain, formed after Hitler invaded the Soviet Union in June 1941 and the USA entered the war in December 1941. The three powers were united by the shared aim of defeating Nazi Germany but held very different long-term goals, since the USA and Britain were capitalist democracies and the USSR was a one-party communist state under Stalin. As victory approached, their leaders met at three wartime conferences, Tehran (November 1943), Yalta (February 1945) and Potsdam (July-August 1945), to plan the final defeat of Germany and the shape of the post-war world. Agreement was easier at Tehran and Yalta, when a common enemy still had to be beaten, and harder at Potsdam, when new disagreements over Poland, free elections and the atomic bomb began to expose the mistrust that would grow into the Cold War.
Before you start
No specific prerequisites - this is a good place to start.
Method
- Learn what each conference agreed, in order: Tehran (1943) agreed the USA and Britain would open a second front in France and the USSR would join the war against Japan once Germany was defeated; Yalta (1945) agreed to divide Germany into four occupation zones, to hold free elections in liberated countries, and to found the United Nations; Potsdam (1945) confirmed Germany's new western border and reparations but exposed disagreement over free elections in Eastern Europe and Poland's government.
- Learn why agreement got harder over time: at Tehran and Yalta the Allies still needed each other to beat Germany; by Potsdam Germany was defeated, Roosevelt (a leader Stalin trusted more) had died and been replaced by Truman, and Churchill had been replaced mid-conference by Attlee after a general election, so the personal relationships that had held the alliance together had weakened.
- Learn the atomic bomb's role at Potsdam: Truman told Stalin the USA had a powerful new weapon, and the USA dropped atomic bombs on Hiroshima (6 August 1945) and Nagasaki (9 August 1945), which ended the war with Japan but also gave the USA a monopoly on nuclear weapons that alarmed Stalin.
- For 'explain two consequences of...' questions, pick two DIFFERENT consequences (for example, one about Germany's occupation and one about growing distrust), and for each one write a short chain: the event, then what it caused, then a specific supporting detail.
- For 'write a narrative account analysing...' questions covering this period, put the three conferences in strict date order and use linking phrases (before this, following this, as a result of this) to show how each conference's outcome shaped the next one, rather than describing the three conferences as separate, unconnected events.
- Keep the wartime alliance separate from what came after it in your own head: this topic is about cooperation surviving under strain, not yet about open hostility, so avoid writing about NATO, the Marshall Plan or the Berlin Blockade here.
Worked example
Write a narrative account analysing the key events in relations between the wartime Allies from the Tehran Conference in November 1943 to the Potsdam Conference in 1945. You may use the following information to help write your answer: the Tehran Conference; the Yalta Conference. You must also use information of your own.
- List the events you will use in date order first: Tehran (November 1943), Yalta (February 1945), the death of Roosevelt and Germany's surrender (April-May 1945), and Potsdam (July-August 1945). A narrative account is marked on this sequence and the links between its parts, so plan the order before you start writing.
- Open with Tehran: explain what was agreed (a second front in France, Soviet entry into the war against Japan) and why the Allies could agree easily at this point, since defeating Germany was still the shared priority.
- Link forward to Yalta with a connecting phrase: 'Following the success of the agreements made at Tehran, the Allies met again at Yalta in February 1945, once Germany's defeat was close.' Explain what was agreed there (occupation zones, free elections, the United Nations).
- Link forward again: 'Before the next conference could take place, Roosevelt died in April 1945 and Germany surrendered in May, removing the shared goal that had held the Alliance together.' This shows you understand what changed between Yalta and Potsdam, not just what happened at each conference.
- Close with Potsdam: explain how the changed circumstances (new leaders, no common enemy, the atomic bomb) meant this conference exposed disagreements over Poland and free elections that Tehran and Yalta had managed to avoid.
- Check your account reads as one connected story with dates and named links, not three separate mini-summaries of each conference.
Practice questions
Try each question, then tap to reveal the answer.
Q1Which two events in 1941 turned the USA and the USSR into wartime allies of Britain?Show answer
Answer: Hitler's invasion of the USSR in June 1941, and Japan's attack on Pearl Harbor in December 1941, which brought the USA into the war.
Q2What did the Allies agree at the Tehran Conference in November 1943?Show answer
Answer: That the USA and Britain would open a second front against Germany in France, and that the USSR would join the war against Japan once Germany was defeated.
Q3Name the three leaders who attended the Yalta Conference in February 1945.Show answer
Answer: Franklin Roosevelt (USA), Winston Churchill (Britain) and Joseph Stalin (USSR).
Q4Give two changes in personnel that had taken place by the time of the Potsdam Conference in 1945.Show answer
Answer: Roosevelt had died and been replaced by Truman, and Churchill had been replaced mid-conference by Attlee after Britain's general election.
Q5State one disagreement that emerged at the Potsdam Conference.Show answer
Answer: Truman and Stalin disagreed over free elections and the type of government that should be allowed in Poland and the rest of Soviet-occupied Eastern Europe.
Q6On what dates were atomic bombs dropped on Hiroshima and Nagasaki?Show answer
Answer: Hiroshima on 6 August 1945 and Nagasaki on 9 August 1945.
Q7Why did agreement between the Allies become harder at Potsdam than it had been at Tehran?Show answer
Answer: Because the shared goal of defeating Germany had been achieved, the leaders who had built trust with Stalin were gone, and the USA's atomic bomb gave it a new source of power and suspicion between the former allies.
Exam-style questions
Written in the style of a GCSE History exam paper, with a full mark scheme.
Explain two consequences of the Yalta Conference of February 1945 for relations between the Allies.
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Write a narrative account analysing the key events in the breakdown of trust between the wartime Allies from the Yalta Conference in February 1945 to the Potsdam Conference in July-August 1945. You may use the following information to help write your answer: the death of President Roosevelt; the surrender of Germany. You must also use information of your own.
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See real GCSE History past-paper questions, with official mark schemes →
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