Causes of
World War II
Explore the political, economic, and ideological forces that plunged the world into its deadliest conflict: from the Treaty of Versailles to the rise of totalitarianism.
The Legacy of World War I
World War II did not emerge from a vacuum. The unresolved tensions of the Great War (1914-1918) created a foundation of resentment, economic instability, and political fragmentation that made another global conflict almost inevitable.
Understanding World War II requires examining four interconnected causes: the Treaty of Versailles, the Great Depression, the rise of totalitarian regimes, and the failure of collective security.
Essential Vocabulary
The Treaty of Versailles (1919)
The Treaty of Versailles imposed crushing terms on Germany after World War I. These provisions created deep resentment among the German people and provided fertile ground for extremist movements.
Road to War: A Timeline
The Great Depression and Political Extremism
Rise of Totalitarian Regimes
Ideology: Fascism, racial supremacy, Lebensraum (living space)
Power: 1933
Ideology: Fascism, imperial expansion, corporatism
Power: 1922
Ideology: Militarism, pan-Asian empire
Power: Military dominance by 1931
How Ideology Drove Expansion
Appeasement vs. Collective Security
| Appeasement | Collective Security | |
|---|---|---|
| Definition | Granting concessions to aggressors | Nations jointly opposing aggression |
| Key Example | Munich Agreement (1938) | League of Nations (1920) |
| Advocates | Chamberlain, Daladier | Wilson, later FDR |
| Outcome | Emboldened Hitler's expansionism | Failed without U.S. membership or enforcement |
| Fatal Flaw | Assumed aggressors had limited goals | No military force to enforce decisions |
Failure of the League of Nations
How to Analyze Causes on the AP Exam
Case Study: The Munich Agreement
Case Study: The Nazi-Soviet Pact (1939)
In August 1939, two ideological enemies stunned the world by signing a non-aggression pact. This agreement contained a secret protocol dividing Eastern Europe into spheres of influence.
Japan's Path to War in the Pacific
Common Mistakes to Avoid
Four Pillars of Causation
| Cause Category | Key Events | Why It Mattered |
|---|---|---|
| Treaty of Versailles | War Guilt Clause, reparations, territorial losses | Created German resentment, economic ruin, desire for revenge |
| Great Depression | Stock market crash, mass unemployment, bank failures | Destabilized democracies, empowered extremist parties |
| Totalitarian Regimes | Rise of Hitler, Mussolini, Japanese militarists | Aggressive expansion, arms buildup, territorial demands |
| Failed Diplomacy | League of Nations, Munich Agreement, appeasement | No enforcement, emboldened aggressors, delayed confrontation |
Question 1 of 5
Which provision of the Treaty of Versailles was most directly responsible for fueling German nationalism and resentment?
Question 2 of 5
The policy of appeasement is best illustrated by which event?
Question 3 of 5
What was the primary significance of the Nazi-Soviet Pact (August 1939)?
Question 4 of 5
Historian A: "The Great Depression was the decisive cause of World War II. Without the economic collapse, Hitler would never have gained mass support. Germany's Weimar democracy was functioning, however imperfectly, until unemployment destroyed public faith in democratic institutions."
Historian B: "The Treaty of Versailles made another war inevitable. The punitive terms created a permanent sense of grievance that any skilled demagogue could exploit. Economic hardship merely accelerated a process already set in motion by the peace settlement of 1919."
On what point do the two historians disagree?
Question 5 of 5
Which of the following best explains why the League of Nations failed to prevent aggression in the 1930s?