Overview
AMSCO Topic 7.9, Causation in Global Conflict (AMSCO p. 531-539), is the capstone chapter for Unit 7 of AP World History: Modern. Instead of introducing new events, it pulls together everything from Topics 7.1-7.8 and asks one big question: what were the most significant causes of global conflict from 1900 to the present? The chapter sorts causes into political and economic categories, traces the effects of the world wars (massive death tolls, revolutions, decolonization, and a power shift from Western Europe to the United States), and closes with four scholars' competing explanations for why totalitarianism rose in the 20th century.
This is a causation skills chapter, so think of it as your argument toolkit for Unit 7 essays. Every table below is essentially a pre-built body paragraph.
Political Causes of Global Conflict in the 20th Century
The big political causes were nationalism, entangling alliances, an arms race, and imperial rivalry. These forces turned a regional crisis in the Balkans into World War I, and extreme versions of the same forces produced World War II two decades later.
Historians call World War I the first "total war." It was fought on an industrial scale with soldiers from around the world, including colonial troops, and new weapons like long-range artillery, poison gas, flamethrowers, and machine guns killed millions on both sides.
| Cause | Significance | Impact |
|---|---|---|
| Nationalism | A growing force for political change across Europe; Serbian nationalism sparked conflict in the Balkans, the "powder keg of Europe." | The spark spread the war throughout Europe. |
| Balance of power and alliances | A 19th-century system of shifting alliances designed to keep peace instead created entangled commitments. | Nations jumped into the war to honor alliances, escalating its scope. |
| Arms race | Competition among Europe's great powers for military superiority. | Made war more likely and deadlier when it came. |
| Imperial rivalry | Western nations, plus Japan and Russia, competed for commerce and access to resources. | Raised tensions that fed both world wars. |
Colonial soldiers serving with the British Army in WWI show just how global the war was: India sent about 1,500,000 soldiers, Canada 418,218, Australia 331,814, New Zealand 112,223, South and East Africa 76,164, and the West Indies 16,000.
For World War II, the same ingredients reappear in stronger doses. Fascism was nationalism in extreme form. The fascist governments of Germany and Italy defied treaties and international pressure when they invaded neighboring territories, and Great Britain and France failed to respond strongly to Germany's aggressive militarism. In the Pacific, Japan's imperial ambitions in Asia were the main cause of war with the United States. For the full event-by-event breakdowns, see the AMSCO 7.2 Causes of World War I notes and the AMSCO 7.6 Causes of World War II notes.
Economic Causes of Global Conflict in the 20th Century
The primary economic cause of global conflict was the fight to acquire and control markets and resources. As the Industrial Revolution spread from Great Britain to Western Europe, then to the United States, Russia, and Japan, industrialized powers needed both raw materials and markets to sell consumer goods, which drove imperialist policies and competition.
| Cause | Significance | Impact |
|---|---|---|
| Control of markets and resources | Western governments (followed by the U.S., Russia, and Japan) took control of trade and territory in Asia and Africa. | Economic rivalry was a root cause of the Opium Wars, the Sino-Japanese Wars, the Crimean War, and both world wars. |
| Industrialization | Spreading industrialization increased demand for raw materials and consumer markets. | Made control of markets a primary motive of imperialism. |
| The Great Depression (1929-1939) | High unemployment and low wages created economic desperation. | Fueled the rise of populist leaders like Adolf Hitler who promised to rebuild their economies. |
The clearest case study is Japan and Pearl Harbor. Japan wanted territory in Asia to secure oil, rice, rubber, and other raw materials. The United States and other countries responded with an embargo cutting off U.S. oil and steel exports to Japan. Japan then attacked the U.S. Pacific Fleet at Pearl Harbor, Hawaii, which brought the United States into World War II. That chain (resource hunger, embargo, attack) is a ready-made causation example for an essay. The interwar economic crisis itself is covered in the AMSCO 7.4 Economy in the Interwar Period notes.
Effects of Global Conflict in the 20th Century
The world wars killed unprecedented numbers of people, toppled empires, redrew the map through decolonization, and shifted power from Western Europe to the United States and the Soviet Union.
| Effect | What happened | Examples |
|---|---|---|
| Massive loss of life | New military technology made war deadlier for soldiers and civilians alike. | Large-scale aerial bombing of populated areas, the atomic bomb, policies targeting minority groups (the Holocaust), plus mass starvation and crimes against humanity. |
| Political revolutions and regime change | War and weak or corrupt leadership toppled old governments. | The Mexican Revolution produced a new constitution with more political and economic rights (though democracy evolved slowly). WWI brought regime change to the Ottoman and Russian empires: the Ottomans got a Western-style democracy, while the Russian Revolution installed a totalitarian Communist government. |
| Rise of totalitarianism | Resentment of the Treaty of Versailles helped fascists take power. | Germany and Italy's fascist governments appealed to nationalism and the desire to restore national glory, then led their nations toward war. |
| Independence movements | Wars weakened colonial powers, and Wilson's call for self-determination signaled that colonies could demand independence. | Colonial peoples felt their wartime service earned self-government; when denied, organized independence movements formed or grew. |
| Decolonization after WWII | Colonial powers could no longer afford to maintain empires, so many new states formed. | Colonies with few foreign settlers usually gained independence relatively peacefully; colonies with sizeable settler populations often went through a more violent process. |
| Repositioning of global power | Power shifted within the West from Western Europe to the United States. | The U.S. suffered less destruction than Europe and became the dominant power in the transatlantic relationship; the Soviet Union soon emerged as a rival superpower. |
The largest independence movement by population was in India. Using passive resistance and civil disobedience, Indians won independence from Britain in 1947. Religious and ideological differences led to partition into a Muslim-dominated Pakistan (originally including East Pakistan, now Bangladesh) and a Hindu-dominated India, and tensions between the two countries have produced several military conflicts since. The civilian death toll side of this story connects directly to the AMSCO 7.8 Mass Atrocities notes.
Scholars' Perspectives on Totalitarianism
Scholars disagree about why so many totalitarian states (states with complete control over every aspect of public and private life) emerged in the 20th century. While many countries moved toward democracy, Russia, Germany, Italy, and Spain became dictatorships between the wars. Each scholar explains it through their own discipline.
The economist: Friedrich Hayek
In The Road to Serfdom (1944), Austrian economist Hayek argued totalitarianism grew gradually out of economic policy choices. Western democracies had "progressively abandoned that freedom in economic affairs without which personal and political freedom has never existed in the past." He saw socialism and fascism as two sides of the same coin because both relied on centralized government planning and state power.
The political scientists: Friedrich and Brzezinski
Carl Friedrich and Zbigniew Brzezinski focused on political and ethnic issues instead. The upheaval of World War I unleashed nationalism, and the need to respond to the global depression that followed created fertile ground for strong nationalistic rulers who could rise to power and address ethnic conflict.
The historian: William Shirer
Shirer located Nazism's origins in Germany's distant, distinctive past. Germanic nationalism, authoritarianism, and militarism dated back to the Middle Ages. German history "made blind obedience to temporal rulers the highest virtue of Germanic man, and put a premium on servility." No other country developed Nazism because no other country had Germany's past.
The sociologist: Barrington Moore
In Social Origins of Dictatorship and Democracy (1966), Moore looked for patterns in social structures across countries. He asked why Great Britain, France, and the U.S. became democracies while Japan, China, Russia, and Germany became dictatorships. His answer: democracy requires developing a middle class and breaking the power of the landed aristocracy. Countries that failed at those two steps were more likely to become dictatorships.
This section is perfect DBQ and LEQ practice: same question, four defensible arguments depending on which evidence you emphasize.
Practice Essay Questions from AMSCO
These prompts come from AMSCO World History: Modern 1200-Present, p. 538, and they're great LEQ reps for this topic.
- "Develop an argument that evaluates the extent to which different causes of global conflict are significant in the period 1900 to the present."
- "Adolf Hitler's campaign of terror against Jews in the 1930s and 1940s had its roots in earlier discrimination against Jews in Europe. Develop an argument that evaluates the extent to which the nature of anti-Semitism in Europe from the Middle Ages through World War II shows continuities or changes over time."
- "Conflicts over territory helped cause two world wars in the 20th century, but they also led to self-rule for many peoples worldwide in the 20th and 21st centuries. Develop an argument that evaluates the extent to which territorial holdings from 1900 to present show continuity or change over time."
Strategy tip: for the first prompt, rank your causes. An argument that says "imperial rivalry mattered more than alliances because it drove both world wars and decolonization" earns complexity better than a list that treats every cause equally.
Key Terms to Know
| Term | Why it matters |
|---|---|
| Total war | War fought on an industrial scale mobilizing entire societies; WWI is often called the first one. |
| Nationalism | Intense loyalty to one's nation; Serbian nationalism sparked WWI, and extreme nationalism fueled WWII. |
| Fascism | Nationalism in extreme form; the governing ideology of Germany and Italy that defied treaties and invaded neighbors. |
| Balance of power | The 19th-century European system of shifting alliances meant to prevent war, which instead escalated WWI. |
| Arms race | Military buildup competition among Europe's great powers that raised the odds of war. |
| Imperial rivalry | Competition over commerce and resources among Western powers, Japan, and Russia; a root cause of both world wars. |
| Great Depression (1929-1939) | Global economic crisis whose unemployment and low wages helped populist leaders like Hitler rise to power. |
| Pearl Harbor | Japan's 1941 attack on the U.S. Pacific Fleet after a U.S. oil and steel embargo; it brought the U.S. into WWII. |
| Treaty of Versailles | The WWI peace agreement; resentment of it helped totalitarian regimes rise in Germany and Italy. |
| Self-determination | Woodrow Wilson's principle that peoples should choose their own government; colonies read it as a right to independence. |
| Mexican Revolution | Early-century revolution demanding political and economic reform; produced a new constitution with broader rights. |
| Russian Revolution | Toppled the tsarist monarchy and installed a totalitarian government led by the Communist Party. |
| Partition of India | The 1947 division of British India into Muslim-dominated Pakistan and Hindu-dominated India after independence won through civil disobedience. |
| Totalitarianism | A state with complete control over every aspect of public and private life; rose in Russia, Germany, Italy, and Spain between the wars. |
| Superpower | The post-WWII status of the United States and the Soviet Union as the world's two dominant rivals. |
| The Road to Serfdom | Hayek's 1944 book arguing totalitarianism grew from abandoning economic freedom; socialism and fascism as two sides of one coin. |
Practice and Next Steps
Reinforce this topic with the 7.9 Causation in Global Conflict course study guide, which covers the same material from the course-topic angle. Since 7.9 is a synthesis chapter, it's also worth circling back through the full set of Unit 7 AMSCO notes, starting with 7.1 Shifting Power, to make sure each cause connects to specific events you can cite as evidence.
Then put the skills to work:
- Drill multiple choice with AP World guided practice on Unit 7 questions.
- Write one of the AMSCO essay prompts above and run it through FRQ practice with instant scoring to see how your thesis and evidence hold up.
- Browse the FRQ question bank for more causation-style LEQs from this period.
Frequently Asked Questions
What is AMSCO Topic 7.9 Causation in Global Conflict about?
AMSCO 7.9 (p. 531-539) is the synthesis chapter for Unit 7. It organizes the causes of global conflict from 1900 to the present into political causes (nationalism, alliances, the arms race, imperial rivalry) and economic causes (competition for markets and resources, the Great Depression), then covers effects like decolonization, revolutions, and the U.S.-Soviet power shift.
What were the main causes of global conflict from 1900 to the present?
The political causes were nationalism (Serbian nationalism sparked WWI), the European alliance system, the arms race, and imperial rivalry. The main economic cause was competition to control markets and resources, intensified by industrialization. The Great Depression also fueled conflict by helping populist leaders like Hitler rise to power.
Why do scholars disagree about the rise of totalitarianism?
Each scholar explains it through their own discipline. Economist Friedrich Hayek blamed the abandonment of economic freedom, political scientists Friedrich and Brzezinski pointed to WWI upheaval plus the global depression, historian William Shirer traced Nazism to Germany's authoritarian past, and sociologist Barrington Moore argued countries without a strong middle class became dictatorships. The same evidence supports multiple defensible arguments, which is exactly what causation essays reward.
Did economic factors really cause Japan to attack Pearl Harbor?
Yes, that's the chain AMSCO lays out. Japan wanted Asian territory to secure oil, rice, rubber, and other raw materials, so the United States imposed an embargo cutting off oil and steel exports to Japan. Japan responded by attacking the U.S. Pacific Fleet at Pearl Harbor, which brought the United States into World War II.
How does Topic 7.9 show up on the AP World exam?
Topic 7.9 is a causation skills topic, so it appears in LEQ and DBQ prompts asking you to evaluate the relative significance of causes of global conflict from 1900 to the present. Practicing a ranked-causes argument (deciding which cause mattered most and why) is the best prep. You can write one and score it with Fiveable's FRQ practice.