Why did the League of Nations fail to keep the peace, and how did this help cause the Second World War?
Explain why the League of Nations failed to prevent aggression in the 1930s and how this contributed to the outbreak of the Second World War
A clear N(A)-Level answer on why the League of Nations failed. Its weaknesses, the absence of key powers, its failure over Manchuria and Abyssinia, and how its collapse encouraged aggression and helped cause the Second World War.
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
This dot point asks you to explain why the League of Nations failed to keep the peace in the 1930s and how this failure helped cause the Second World War. The League was set up after the First World War to stop future wars by getting countries to settle their disputes peacefully. You should be able to explain why it was too weak to do this and how its failures encouraged aggressive countries to break the peace. The key idea is that when an organisation meant to stop aggression proves powerless, aggressors are encouraged to take more, which is exactly what happened on the road to the Second World War.
The answer
What the League was meant to do
The League of Nations was created after the First World War to keep world peace. The idea was collective security: if one country attacked another, all the member countries would act together to stop the aggressor, by talking, by stopping trade with it (called sanctions), or, in theory, by force. The hope was that no country would dare break the peace if it faced the whole world united against it. On paper this was a fine idea, but in practice the League had serious weaknesses.
Missing powers
A major weakness was that important countries were not members. The United States, the most powerful country in the world, never joined, because its own parliament refused. This robbed the League of great strength and authority from the start. Over time other powers, such as Germany, Japan and Italy, either left the League or were never reliable members. With key countries outside it, the League often could not present the united front its whole idea depended on.
No army and slow to act
The League also had no army of its own. If an aggressor ignored its decisions, the League could only ask member countries to provide forces, and they were usually unwilling to risk their own soldiers and money. The League worked slowly too, because it needed its members to agree before it could act. Sanctions, its main weapon, were often weak because countries did not want to harm their own trade. So even when the League decided something was wrong, it struggled to do anything effective about it.
The failure over Manchuria
The League's weakness was first clearly exposed when Japan invaded Manchuria, a region of China, in 1931. China appealed to the League for help. The League investigated and condemned Japan, but it could do nothing to make Japan leave. Japan simply ignored the League and then walked out of it. The lesson for the world was alarming: a major power could invade another country and the League was powerless to stop it. Aggressors took note.
The failure over Abyssinia and the road to war
The League's reputation was destroyed completely when Italy, led by Mussolini, invaded Abyssinia (now Ethiopia) in the mid-1930s. Again the League condemned the aggression and ordered sanctions, but the sanctions were too weak to stop Italy, and key members did not want to push Italy too far. Italy conquered Abyssinia anyway. After this, no one took the League seriously. Its failures taught Hitler, Mussolini and Japan that aggression would not be punished, which encouraged the further aggression that led to the Second World War.
Examples in context
Example 1. Japan walks out. When the League condemned Japan over Manchuria, Japan's response was simply to leave the organisation and keep what it had conquered. This showed that membership of the League was voluntary and that a determined aggressor could ignore the League and walk away. It was a clear warning that the League could not enforce its will on a major power.
Example 2. Weak sanctions on Italy. During the Abyssinian crisis the League imposed sanctions on Italy, but it deliberately left out the most important materials, such as oil, partly because some members did not want to drive Italy into Hitler's arms. These half-hearted sanctions failed to stop the invasion and made the League look both weak and hypocritical, finishing off its reputation.
Try this
Cue. Explain the idea of collective security and why the absence of the United States made it so hard for the League to work.
Cue. Describe what happened when Japan invaded Manchuria and explain why the League's response failed.
Cue. Explain how the failures over Manchuria and Abyssinia encouraged further aggression and helped lead to the Second World War.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original8 marksExplain why the League of Nations failed to prevent aggression in the 1930s.Show worked answer →
- Point of view
- The League failed mainly because it was too weak to enforce its decisions, so aggressive countries simply ignored it.
- Reason 1 (missing powers)
- Key powers were absent. The United States never joined, and others left, so the League lacked the strength to act against aggressors.
- Reason 2 (no army and slow action)
- The League had no army of its own and worked slowly, so it could not stop aggression quickly or by force.
- Reason 3 (failures over Manchuria and Abyssinia)
- When Japan invaded Manchuria and Italy invaded Abyssinia, the League did nothing effective, which exposed its weakness.
- Conclusion
- Because the League was weak and its members unwilling to act, aggressive states learned they could break the peace without punishment.
What markers reward: a clear point of view about weakness, the absence of key powers, the lack of an army, the failures over Manchuria and Abyssinia, and a judgement.
Original7 marksStudy the source. A paraphrased British cartoon from the mid-1930s shows the League of Nations as a frail old man shaking his finger at a heavily armed soldier who is laughing and walking away. What does this source suggest about the League of Nations? Support your answer with details from the source.Show worked answer →
- Message
- The source suggests the League of Nations was weak and powerless, unable to stop aggressive, well-armed countries from doing as they pleased.
- Support from the source
- Showing the League as a "frail old man" suggests it was weak and lacked real strength. The armed soldier "laughing and walking away" suggests aggressors did not take the League seriously and ignored its protests.
- Brief explanation
- This fits the real failures of the League, such as over Manchuria and Abyssinia, where it could only protest while aggressors acted freely.
What markers reward: an inference about the League's weakness and lack of authority, two details from the source used as support, and a short link to the League's real failures.
Related dot points
- Explain how Hitler's foreign policy aims and his steps of expansion in the 1930s increased the risk of another European war
A clear N(A)-Level answer on how Hitler's foreign policy led to war. His aims, rearmament, the Rhineland, the union with Austria, the takeover of Czechoslovakia, and how to explain his step-by-step expansion.
- Explain the policy of appeasement, why Britain and France followed it, and how the invasion of Poland led to war in 1939
A clear N(A)-Level answer on appeasement and the outbreak of the Second World War. What appeasement was, why Britain and France followed it, the Munich Agreement, the Nazi-Soviet Pact, and how the invasion of Poland led to war.
- Explain how economic crisis, nationalism and the power of the army led to military domination of Japan in the 1930s
A clear N(A)-Level answer on how the military came to dominate Japan in the 1930s. The effects of the Depression, the need for resources, the rise of nationalism and the army, the invasion of Manchuria, and how to explain the drift to aggression.
- Describe the main terms of the Treaty of Versailles and explain why Germans resented the settlement
A clear N(A)-Level answer on the Treaty of Versailles. The main terms covering blame, money, land and the army, why Germans resented the treaty, and how to use the easy memory tool BRAT to organise an answer.