AP World History: Modern

## Learning Outcomes

- Explain how **fascism** and militarism encouraged expansionist foreign policy
- Identify the main acts of territorial aggression by **Japan, Italy, and Germany** in the 1930s
- Understand why **Britain and France** followed appeasement
- Explain why the **League of Nations** and collective security failed
- Distinguish between long-term causes of World War II and the immediate trigger in **1939**
- Use specific evidence, dates, and examples in AP-style causation arguments

## AP World History: Modern Syllabus

For the AP World History: Modern, you are expected to understand the causes of World War II through fascism, appeasement, and territorial aggression, with a focus on the following syllabus points:

![Fascism, militarism, appeasement, and territorial aggression leading to the outbreak of war in Europe in 1939.](https://static.pastpaperhero.com/images/ap-world-history-modern-causes-of-world-war-ii-fascism-appeasement-and-territorial-aggression_00.png)

_Japanese, Italian, and German acts of aggression are situated alongside appeasement and collective security's breakdown before the invasion of Poland._

- Know that **fascist** and militarist regimes promoted nationalism, dictatorship, rearmament, and expansion
- Identify key acts of aggression: **Japan in Manchuria (1931)**, **Italy in Ethiopia (1935)**, and **Germany in the Rhineland (1936), Austria (1938), Czechoslovakia (1938–1939), and Poland (1939)**
- Understand the meaning of **appeasement** and why Britain and France used it
- Explain why the **League of Nations** and the idea of **collective security** failed in the 1930s
- Know the importance of the **Munich Agreement (1938)** as the clearest example of appeasement
- Understand why the occupation of the rest of **Czechoslovakia in 1939** mattered
- Identify the significance of the **Nazi-Soviet Pact (August 23, 1939)**
- Know that the invasion of **Poland on September 1, 1939** triggered war in Europe

## Test Your Knowledge

_Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, look more closely at that area during your revision._

1. Why did fascist governments tend to support territorial expansion?
2. What was appeasement, and why did Britain and France choose it?
3. Name two examples of aggression that showed the weakness of the League of Nations.
4. Why did Hitler’s occupation of the rest of Czechoslovakia in 1939 change European opinion?
5. How did the Nazi-Soviet Pact make war more likely?

## Introduction

The causes of World War II are one of the most important causation topics in Unit 7. On the AP exam, this topic is not just about listing events. You need to explain how ideas, policies, and actions connected. Fascism encouraged aggression. Weak responses from other powers reduced deterrence. Each successful act of expansion made the next one easier.

This topic sits in **Period 4 (c. 1900–present)** and connects strongly to the AP themes of **GOV** and **ECN**. Governments changed after World War I, and the global economy was shaken by the Great Depression. Those changes helped extremist states gain support, then act more aggressively abroad.

> **Key Term: fascism**
> An authoritarian, ultranationalist ideology that emphasizes dictatorship, militarism, obedience, and suppression of opposition.

### Why fascism and militarism pushed states toward expansion

Fascism mattered because it was not only a domestic system of rule. It also shaped foreign policy. Fascist leaders treated compromise as weakness and military success as proof of national greatness. If a regime teaches that the nation must be strong, unified, and feared, then expansion by force can look justified rather than criminal.

In **Italy**, Benito Mussolini promised to restore greatness similar to that of the Roman Empire. That goal encouraged overseas conquest. In **Germany**, Adolf Hitler fused fascism with racial ideology and the demand to overturn the **Treaty of Versailles**. He argued that Germany needed rearmament, unity of all German-speaking peoples, and **Lebensraum**, or “living space,” especially in eastern Europe. In **Japan**, AP World usually uses the term **militarism** rather than treating Japan as identical to European fascism. Still, the result was similar: army leaders, emperor-centered nationalism, and the belief that expansion in Asia was necessary for security, prestige, and resources.

> **Key Term: militarism**
> A political approach that glorifies military strength and gives armed forces major influence over government and policy.

The economic situation made these ideologies more appealing. The **Great Depression** discredited moderate governments. In Germany, mass unemployment and political deadlock weakened support for the Weimar Republic and boosted extremist parties. In Japan, falling trade and economic stress strengthened those who argued that empire would solve shortages of raw materials and markets. In Italy, expansion could be presented as a way to distract from domestic weakness and prove national strength.

This is an important AP causation point: economic crisis did not automatically cause war. Instead, it increased support for regimes that favored aggressive solutions. That is a stronger argument than simply saying “the Depression caused World War II.”

> **Key Term: Treaty of Versailles**
> The 1919 treaty ending World War I that imposed military restrictions, reparations, and territorial losses on Germany.

Students often make a weak argument here by treating the Treaty of Versailles as the only cause. It was important, but mainly because Hitler used German resentment of it. Versailles created anger over reparations, military limits, and war guilt. That anger became dangerous when paired with fascist leadership, rearmament, and foreign weakness.

> **Test Tip:**
> In an LEQ or DBQ, avoid saying one factor “caused World War II” by itself. Strong AP answers show a chain: Versailles resentment and Depression instability helped extremist regimes rise; those regimes promoted expansion; weak resistance encouraged more aggression.

### Territorial aggression and the collapse of collective security

The 1930s showed, step by step, that aggressive states could break rules without facing decisive punishment. That is why historians often describe the road to World War II as an escalation.

> **Key Term: collective security**
> The principle that states should act together against aggression in order to preserve peace.

The first major test came in **1931**, when Japan invaded **Manchuria** in northeastern China after the **Mukden Incident**. Japan created the puppet state of **Manchukuo**. The League of Nations condemned the action slowly, but it had no army of its own and depended on member states to act. They did not. Japan simply left the League in **1933**.

This mattered beyond East Asia. It taught all revisionist powers that the League was weak. If one aggressive state could seize territory and walk away from criticism, others might do the same.

The second major test was **Italy’s invasion of Ethiopia in 1935**. Ethiopia, also called Abyssinia, was one of the few independent African states. The League imposed sanctions, but they were limited and ineffective. Oil was not cut off, and major powers did not commit to military enforcement. Italy conquered Ethiopia anyway.

This was another major blow to collective security. The lesson was clear: a rule is only as strong as the willingness to enforce it.

Germany then pushed hardest in Europe. In **1935**, Hitler openly rearmed Germany and introduced conscription, violating Versailles. In **March 1936**, he remilitarized the **Rhineland**, which had been kept demilitarized to protect France. This was a gamble. German forces were not yet ready for a major war, and Hitler later admitted that a firm French response might have forced retreat.

But no such response came.

That is why the Rhineland is so important. It was not only a treaty violation. It was a test of will. Britain and France failed it. Hitler learned that his opponents were cautious, divided, and unwilling to act early.

The **Spanish Civil War (1936–1939)** deepened this pattern. Germany and Italy supported **Francisco Franco**’s nationalist forces. The Soviet Union assisted the republican government. Britain and France followed nonintervention. Germany and Italy gained influence, tested weapons and tactics, and saw again that democracies hesitated.

In **1937**, Japan expanded its war in China and committed the **Rape of Nanjing**, an atrocity that showed how brutal expansionist warfare had become. By this stage, aggression was clearly multinational, not just German.

A useful AP comparison is this:

- **Japan** challenged peace in East Asia
- **Italy** challenged peace in Africa
- **Germany** challenged peace in Europe

Together, these cases show that World War II had global roots before it became a global war.

> **Test Tip:**
> If a prompt asks about the “causes of World War II,” score better by using examples across regions. Do not focus only on Germany when Japan in Manchuria and Italy in Ethiopia also show the breakdown of peace.

### Appeasement: why Britain and France made concessions

> **Key Term: appeasement**
> A policy of making concessions to an aggressive power in hopes of avoiding war.

Appeasement is often simplified as cowardice. That is too weak for AP analysis. Britain and France had reasons for using it, even if the policy failed.

First, the memory of **World War I** was overwhelming. Leaders and publics remembered trench warfare, mass death, and economic ruin. Avoiding another war looked sensible.

Second, both countries were **militarily unprepared** in key ways. Britain wanted more time for rearmament, especially in the air. France relied heavily on defense, including the **Maginot Line**, and feared another devastating land war.

Third, the **Great Depression** limited resources and political confidence. Economic weakness made governments cautious.

Fourth, many British and French leaders believed that parts of the **Versailles settlement had been too harsh** on Germany. Some demands, especially involving German-speaking peoples, seemed negotiable to them.

Fifth, anti-communism mattered. Some policymakers viewed Nazi Germany as a barrier against Soviet communism and distrusted cooperation with the USSR.

This context helps explain the most famous case: the **Munich Agreement**, signed on **September 29–30, 1938**.

Germany demanded the **Sudetenland**, a border region of Czechoslovakia with many German speakers. At Munich, Britain, France, Germany, and Italy agreed to let Hitler take the region. **Czechoslovakia was not invited**, and neither was the Soviet Union. British Prime Minister **Neville Chamberlain** believed the concession would preserve peace.

> **Key Term: Munich Agreement**
> The 1938 agreement allowing Germany to annex the Sudetenland from Czechoslovakia in return for Hitler’s promise not to expand further.

Munich is the clearest example of appeasement because it shows all its features: concession, exclusion of the smaller state affected, and faith that satisfying limited demands would stop wider aggression.

Why did Munich fail? Because Hitler did not interpret concessions as fairness. He interpreted them as weakness. Appeasement gave Germany strategic gains without war, damaged Czechoslovakia, and showed that Britain and France would retreat under pressure.

### From Anschluss to Poland: the final steps to war

In **March 1938**, Germany carried out the **Anschluss**, annexing Austria. Hitler justified it partly through ethnic nationalism, claiming to unite German-speaking peoples. Some outside observers still told themselves that his aims were limited.

That illusion collapsed in **March 1939**, when Germany occupied the rest of **Czechoslovakia**.

This was a turning point because the rest of Czechoslovakia was not simply a German-speaking borderland. By taking it, Hitler proved that his aims went beyond self-determination for Germans. He wanted expansion and domination.

> **Key Term: Anschluss**
> The annexation of Austria by Nazi Germany in March 1938.

Once Hitler occupied all of Czechoslovakia, Britain and France could no longer easily argue that his demands were limited or reasonable. They gave guarantees to **Poland**.

But one final diplomatic move changed everything: the **Nazi-Soviet Pact**, also called the **Molotov-Ribbentrop Pact**, signed on **August 23, 1939**.

> **Key Term: Nazi-Soviet Pact**
> A nonaggression agreement between Germany and the Soviet Union that included secret plans to divide parts of Eastern Europe, especially Poland.

Why would Hitler and Stalin cooperate? Because each had immediate goals. Hitler wanted to invade Poland without facing a two-front war. Stalin no longer trusted Britain and France after Munich and the failure of collective security. The pact gave him time and territory.

This is one of the most tested distinctions in the topic. The pact did not begin the war by itself. But it removed a key obstacle to German invasion.

On **September 1, 1939**, Germany invaded **Poland**. On **September 3**, Britain and France declared war on Germany.

That was the immediate start of World War II in Europe.

Students often confuse this with Munich. Munich **emboldened** Hitler. The invasion of Poland **triggered** war.

### How to build an AP argument on this topic

For AP World, this topic often appears as a causation LEQ or as outside evidence in a DBQ on global conflict. A strong argument should separate:

- **Long-term causes:** Versailles resentment, Great Depression, League weakness, fascist and militarist ideologies
- **Escalating causes:** Manchuria, Ethiopia, Rhineland, Spanish Civil War, Anschluss, Sudetenland
- **Immediate causes:** occupation of Czechoslovakia, Nazi-Soviet Pact, invasion of Poland

A simple high-scoring thesis model could look like this: World War II was caused not by one event alone but by the rise of fascist and militarist states, repeated territorial aggression in Asia, Africa, and Europe, and the failure of collective security and appeasement, which encouraged further expansion until Germany’s invasion of Poland in 1939 triggered war in Europe.

That kind of answer works because it is specific, regional, and causal.

## Key Point Checklist

_This article has covered the following key knowledge points:_

- Fascism in Italy and Nazism in Germany encouraged militarism, dictatorship, and expansion
- Japanese militarism also promoted aggressive imperial expansion, especially for resources and influence
- The Treaty of Versailles contributed to German resentment, which Hitler exploited politically
- The Great Depression weakened democracies and increased support for extremist regimes
- Japan invaded Manchuria in 1931, showing the weakness of the League of Nations
- Italy invaded Ethiopia in 1935, and League sanctions failed to stop it
- Germany remilitarized the Rhineland in 1936, and Britain and France did not act
- The Munich Agreement of 1938 was the clearest example of appeasement
- Germany’s occupation of the rest of Czechoslovakia in March 1939 showed Hitler’s goals went beyond self-determination
- The Nazi-Soviet Pact of August 1939 removed the immediate danger of a two-front war for Germany
- Germany’s invasion of Poland on September 1, 1939 triggered World War II in Europe
- Strong AP answers explain the chain linking ideology, aggression, weak enforcement, and the final outbreak of war

## Key Terms and Concepts

- fascism
- militarism
- Treaty of Versailles
- collective security
- appeasement
- Munich Agreement
- Anschluss
- Nazi-Soviet Pact


Causes of World War II - Fascism, appeasement, and territorial aggression