Explain how the events of 1939, including the Nazi-Soviet Pact and the invasion of Poland, led to the outbreak of war in Europe

What this dot point is asking

SEAB wants you to explain how the events of 1939 led to the outbreak of war in Europe, focusing especially on the Nazi-Soviet Pact of August 1939 and the German invasion of Poland in September. You should be able to describe the key steps in order, from Hitler's seizure of the rest of Czechoslovakia in March 1939 through the British guarantee to Poland and the surprise pact with the Soviet Union, to the invasion and the declaration of war. The task is explanation: show how each step followed from the last and why this chain finally brought Britain and France into a war they had long tried to avoid.

The answer

The end of appeasement: Czechoslovakia, March 1939

The first decisive event of 1939 came in March, when Hitler broke his Munich promise and seized the rest of Czechoslovakia. This was crucial because the people he now took over were Czechs, not German-speakers, so Hitler could no longer claim he was simply uniting Germans or righting the wrongs of Versailles. It proved that his aims were unlimited aggression, not just fair grievances. The seizure shocked Britain and France and finally convinced them that appeasement had failed and that Hitler had to be stopped. Public opinion in Britain turned firmly against Hitler.

The guarantee to Poland

After Czechoslovakia, it was clear that Hitler's next likely target was Poland, partly because of his demands over the city of Danzig and the Polish Corridor, which separated East Prussia from the rest of Germany. To deter him, Britain and France took a new and firmer line: they publicly guaranteed to defend Poland's independence. This was a major change from appeasement. It meant that if Germany attacked Poland, Britain and France were committed to going to war. The question was whether Hitler believed they would really fight.

The Nazi-Soviet Pact, August 1939

The most surprising event of 1939 was the Nazi-Soviet Pact, signed in August between Germany and the Soviet Union. Nazi Germany and the communist Soviet Union were bitter ideological enemies, so an agreement between them stunned the world. Publicly it was a promise not to attack each other. Secretly, the two agreed to divide Poland and parts of eastern Europe between them. For Hitler, the pact was a master-stroke: it meant that if he attacked Poland, he would not have to fight the Soviet Union as well, so he avoided the two-front war that Germany dreaded. For Stalin, it bought time to prepare and won territory. The pact removed Hitler's last great obstacle.

The invasion of Poland and the declaration of war

With the Soviet Union neutralised, Hitler was ready. On 1 September 1939, German forces invaded Poland, using fast-moving tactics later called Blitzkrieg. Hitler may have gambled that Britain and France would back down again, as they had over Czechoslovakia. This time they did not. Honouring their guarantee to Poland, Britain and France demanded that Germany withdraw, and when it refused, they declared war on Germany on 3 September 1939. The Second World War in Europe had begun. Poland, attacked by Germany from the west and soon by the Soviet Union from the east, was quickly overrun.

Putting the causes together

The outbreak of war in 1939 was the result of all the longer-term causes coming together. Hitler's aggressive aims and actions had been pushing toward war throughout the 1930s. The failure of the League and the policy of appeasement had failed to stop him and had made him bolder. The events of 1939, the seizure of Czechoslovakia, the Polish guarantee and the Nazi-Soviet Pact, were the final steps. The immediate trigger was the invasion of Poland, but it must be understood against this whole background: Hitler's ambition met by powers who had finally decided to resist.

Examples in context

Example 1. Danzig and the Polish Corridor. Hitler's demands focused on the free city of Danzig and the Polish Corridor, the strip of land created by Versailles that separated East Prussia from the rest of Germany. By presenting these as wrongs of Versailles that needed correcting, Hitler tried to make his pressure on Poland look reasonable. But after Czechoslovakia, Britain and France no longer believed his grievances were limited, which is why they guaranteed Poland rather than negotiate.

Example 2. The shock of the Nazi-Soviet Pact. The pact between Nazi Germany and the communist Soviet Union astonished the world because the two were sworn enemies. Communists abroad were bewildered, and Britain and France, who had hoped the Soviet Union might help contain Hitler, were dismayed. The pact shows how Hitler used ruthless diplomacy to isolate Poland and remove the danger of a two-front war before striking.

Try this

Q1. On what date did Germany invade Poland? [3 marks]

• Cue. 1 September 1939; Britain and France declared war on Germany on 3 September 1939.

Q2. Explain why the seizure of the rest of Czechoslovakia in March 1939 was a turning point. [5 marks]

• Cue. Hitler now took over Czechs, not German-speakers, proving his aims were unlimited; this convinced Britain and France that appeasement had failed and that Hitler had to be resisted, leading to the guarantee to Poland.

Q3. "The Nazi-Soviet Pact was the main reason war broke out in 1939." How far do you agree? [8 marks]

• Cue. Argue the pact freed Hitler to attack Poland and was the final step, but weigh it against Hitler's aggression, the failure of appeasement and the British and French guarantee before judging.