Unit 7: Global Conflict (c.

1900–Present)
7.1 Shifting Power After 1900
• Collapse of Empires: The old land empires disintegrated. China’s Qing Dynasty fell
in the 1911 Xinhai Revolution, ending millennia of imperial rule. Russia’s tsarist
regime was overthrown in 1917 (February and October Revolutions). The Ottoman
Empire was dismantled after WWI – its sultanate was abolished in 1922 and
replaced by the Republic of Turkey.
• New Nation-States: Former imperial territories became new countries. For
example, after WWI Austria-Hungary split into Austria, Hungary, Czechoslovakia
and Yugoslavia; the Baltic states (Latvia, Estonia, Lithuania) and Poland re-
emerged; Turkey replaced the Ottoman core. (The U.S. and USSR also rose as
global powers in this era.)
• Revolution and Reform: Internal upheavals reshaped governments. Mexico’s
1910–20 Revolution toppled dictator Porfirio Díaz and produced a 1917 constitution
with land and labor reforms. The 1919 May Fourth Movement in China and the 1919
March First Movement in Korea galvanized nationalism. Influential new ideologies
emerged (e.g. communism after the 1917 Russian Revolution).
• Anti-Imperial Ideology: The idea of national self-determination (promoted by
Woodrow Wilson and the League of Nations mandates) encouraged colonized
peoples. Colonial troops had fought in WWI and expected change, but Europe
largely kept control – Britain and France maintained their empires, often violently
suppressing nationalist movements. This unprecedented ideological challenge to
colonial rule helped spur Pan-Arab, Pan-African, and other anti-imperial
movements in the interwar years.

7.2 Causes of World War I

(Remember “MAIN”)

• Militarism & Arms Race: European powers built up massive armies and navies (e.g.
Germany’s naval expansion challenged Britain). Military leaders had great influence
on policy.
 • Alliances: Rival blocs formed. The Triple Alliance (1882) linked Germany, Austria-
Hungary and Italy, while the Triple Entente (1907) united France, Britain and
Russia. This meant a conflict involving one power could draw in all.
• Imperialism: Competition for colonies and resources (Africa, Asia) bred distrust.
For example, the Moroccan crises (France vs. Germany) and Agadir Incident (1911)
increased Franco-German hostility.
• Nationalism: Intense national pride and ethnic tensions. Slavic nationalism in the
Balkans threatened Austria-Hungary; Arab and Irish nationalisms also caused
unrest. Many people sought independence or greatness for their nation.

7.3 Conducting World War I

• Total War Mobilization: WWI was a total war. Governments mobilized entire
societies (industry, agriculture, labor) for the war effort. Civilians and soldiers alike
were affected. Economies were centrally directed: price controls, rationing and war
boards became common. (For example, by 1917 many countries were effectively on
a planned-war economy, blurring military and civilian sectors.) Women and older
men worked in factories and farms to replace enlisted soldiers.
• Trench Warfare (Western Front): On the Western Front, both sides dug vast
networks of trenches for protection; trenches—long, deep ditches dug as protective
defenses—are most often associated with World War I, and the results of trench
warfare in that conflict were hellish indeed. Troops endured months in muddy,
disease-ridden trenches. Attacks required climbing out into “no man’s land” under
heavy machine-gun and artillery fire, leading to enormous casualties.
• Modern Weapons: New technology made battles deadly. Machine guns, bolt-
action rifles, heavy artillery and barbed wire made frontal assaults costly. Poison
gas (chlorine, mustard) caused choking deaths and blindness. Tanks (introduced
1916) and airplanes (reconnaissance/bombing) appeared. Submarines (U-boats)
threatened shipping (the Lusitania sinking, 1915). The result was unprecedented
slaughter on land, sea and air.
• Global Combat: The war spread beyond Europe. Colonial subjects (soldiers and
laborers from India, Africa, Australia, etc.) fought overseas or supported home
fronts. Battles raged in the Middle East (Gallipoli, Sinai-Palestine), Africa (East
African campaign) and Asia.
• Casualties and Human Cost: The carnage was immense. Roughly 65–70 million
men served; about 8.5 million soldiers died in battle or from wounds/disease.
Another 6–7 million civilians died from military action, genocide (e.g. Armenian
 Genocide), famine and disease. For example, up to 1 million Armenians were
forcibly marched or killed by the Ottomans in 1915–17. After four years of fighting,
the Allies won, but at a staggering human cost.

7.4 Economy in the Interwar Period

• Postwar Recession & Inflation: The immediate aftermath of WWI saw short-term
booms followed by busts. Many European economies were devastated by war debts
and reparations. Inflation soared in Germany and other countries.
• Great Depression (1929–1930s): The U.S. stock-market crash (1929) triggered a
worldwide Depression. Exports collapsed, unemployment soared, and global trade
plummeted. This economic collapse stressed democracies and helped extremists.
In many countries, government intervention in the economy increased. Keynesian
ideas (deficit spending to spur demand) gained traction.
• State Intervention: Governments took a more active role. Examples include
President Roosevelt’s New Deal programs (public works, regulation, social security)
in the U.S. and Mussolini’s corporate state in Italy. The USSR and, later, Mao’s
China implemented Five-Year Plans for industrialization. Fueled by [the Great
Depression], governments began to take a more active role – FDR’s New Deal,
Mussolini’s corporatism, Soviet Five-Year Plans (These measures helped stabilize
economies but also expanded government power.)
• Political Polarization: Economic hardship undermined faith in liberal democracy.
High unemployment and social unrest made extremist ideologies appealing. For
instance, in Germany and Italy fascist parties capitalized on grievances. During the
worldwide economic crisis of the Great Depression… many people lost faith in
liberal democracy and … turned to authoritarian regimes. Hitler’s Nazi Party rose in
part by promising to restore the economy and national pride.
• Trade Barriers and Debts: Many nations enacted tariffs and protected industries,
worsening global trade decline. War debts and reparations strained international
finance. These unresolved economic issues helped fuel international tensions in
the 1930s.

7.5 Unresolved Tensions After WWI

• Peace Settlement Problems: The Treaty of Versailles (1919) imposed harsh terms
on Germany, sowing resentment. It required heavy reparations, limited Germany’s
military, and redrew borders. German public saw it as a “Diktat” (unfair diktat).
 Similarly, new nations in Eastern Europe had border disputes. Overall, key powers
(US, France, Britain, Japan) had conflicting aims. Many historians note that anger
over Versailles (“revanchism”) helped set the stage for WWII.
• League of Nations Limitations: The League aimed to manage conflicts, but it
lacked enforcement power and key members (US never joined). It failed to resolve
territorial disputes or check aggression. For example, Japan left the League in 1933
after the League condemned its invasion of Manchuria.
• Mandate System and Colonial Friction: Former German and Ottoman colonies
became League mandates under British or French control (e.g. Iraq, Palestine,
Syria). Colonial subjects had hoped for independence. Instead, Western powers
retained most colonies. This fueled nationalist movements. WWI unleashed an
unprecedented ideological challenge to colonial rule – yet Britain and France
maintained their imperial rule, often violently suppressing anti-colonial nationalist
challenges.
• Aggressive Expansionism: Tensions grew as dissatisfied powers took action. Japan
invaded Manchuria in 1931 and set up the puppet state of Manchukuo (aiming for a
Greater East Asia Co-Prosperity Sphere). Italy invaded Ethiopia in 1935 (defying the
League). Germany, remilitarizing the Rhineland (1936), then annexed Austria (1938)
and Czechoslovakia (1938–39) under Hitlers demand for Lebensraum (living space).
These actions proved the postwar order unstable.
• Rise of Nationalism: Across Africa, Asia, and the Middle East, anti-colonial
nationalism grew. Transnational movements (Pan-Arabism, Pan-Africanism) began
organizing, and colonial-educated elites formed political parties (e.g. the Indian
National Congress) to demand rights. These movements were still largely blocked
by imperial powers in the 1920s–30s, but they set the stage for decolonization after
WWII.

7.6 Causes of World War II

• Failure of the Versailles Settlement: Many of WWI’s resolutions bred resentment.
Germany’s humiliating defeat and harsh treaty terms encouraged revanchism. In
the 1930s, Germany’s Weimar Republic was unstable and the Versailles
disarmament provisions were widely seen as illegitimate. Adolf Hitler exploited this
outrage, rearming Germany and repudiating Versailles.
• Economic Depression: The global Depression undermined democracies and
boosted extremist parties. Widespread unemployment and poverty made radical
 solutions appealing. Hitler’s Nazis came to power in 1933 promising economic
recovery and national renewal, in part by defying the postwar order.
• Fascism and Militarism: Authoritarian, expansionist ideologies took hold in
Germany, Italy and Japan. These regimes glorified conquest and racial superiority.
For example, Mussolini’s Italy invaded Ethiopia (1935); Hitler’s Germany
remilitarized the Rhineland and annexed neighbors. Imperial Japan, resource-poor
and militaristic, invaded Manchuria (1931) and later deeper into China. These
aggressions challenged the status quo.
• Alliances and Pacts: New hostile blocs formed. Germany allied with Italy and
Japan (Tripartite Pact, 1940). Stalin’s Soviet Union initially signed the Nazi-Soviet
Pact (1939), secretly agreeing to divide Eastern Europe (Poland) – which
emboldened Hitler to invade Poland.
• Appeasement & Weak Deterrence: Britain and France initially tried to avoid
another war by appeasing Hitler’s demands. At the 1938 Munich Conference, they
allowed Germany to annex the Sudetenland (part of Czechoslovakia), believing it
would satisfy him. In fact, appeasement only encouraged further aggression. The
League of Nations proved powerless to stop invasions of Ethiopia and China.
• Immediate Trigger – Poland Invasion: On Sept 1, 1939, Germany invaded Poland
using blitzkrieg tactics. Britain and France, having guaranteed Polish security,
declared war on Germany. The immediate precipitating event was the invasion of
Poland by Nazi Germany on September 1, 1939 leading directly to World War II.

7.7 Conducting World War II

• Total War on an Even Larger Scale: WWII again mobilized entire societies.
Economies were commandeered for war: factories ran 24/7, men and women
enlisted or worked in arms industries, and governments imposed rationing and
control measures. For example, the U.S. created a war-production board and
instituted the first peacetime draft. By war’s end, American industry had produced
unprecedented quantities of ships, planes and tanks.
• Allied Production and Cooperation: The Allies outproduced the Axis through
combined effort. The U.S. provided massive support to its partners via Lend-Lease –
about $31.4 billion in supplies to Britain and $11.3 billion to the Soviet Union
(billions more to other Allies). This material aid (weapons, ships, food) helped
sustain Britain and the USSR long before America formally entered the war. (The
sheer scale of Allied production – tanks, planes, ships – overwhelmed Axis
industrial capacity by the mid-1940s.)
 • Global Battlefronts: WWII was truly global. Major theaters included Europe and
North Africa (1939–45), the Pacific (1941–45), and Asia (China vs. Japan continued
throughout the war). Key turning points included the Soviet victory at Stalingrad
(1942–43), the Battle of Midway (1942) in the Pacific, and the Allied landings in
Normandy (D-Day, 1944). By mid-1945, the Axis powers were defeated on all fronts
(Germany surrendered May 1945; Japan in Sept. 1945).
• Innovations and Destruction: Technological advances increased killing power.
Strategic bombing devastated cities on both sides (e.g. the German Blitz of London,
Allied firebombing of Dresden and Tokyo). Most dramatically, nuclear weapons
were used: in August 1945 the U.S. dropped atomic bombs on Hiroshima and
Nagasaki, Japan. These bombs immediately killed some 70,000 people in
Hiroshima (and similarly tens of thousands in Nagasaki), illustrating the terrifying
scale of modern warfare.
• Casualties: WWII was the deadliest conflict in history. Estimates put total deaths at
roughly 70–85 million – about 3% of the world’s population in 1940. This includes
about 21–25 million military personnel and ~50–55 million civilians (due to
bombings, genocide, starvation, and disease) The war’s conduct – including the
Holocaust (next section) and other mass atrocities – caused unprecedented
suffering.

Figure: Hiroshima devastated after the August 1945 U.S. atomic bombing (IWM image). The
atomic bombing of Hiroshima on August 6, 1945 immediately killed some 70,000 people
and leveled the city. (Another bomb on Nagasaki three days later killed a comparable
number.) The use of such destructive weaponry helped force Japan’s surrender. The sheer
scale of destruction and loss of life in WWII – far beyond WWI – spurred the creation of the
United Nations (1945) and set the stage for the Cold War power order (U.S. and USSR as
superpowers).

7.8 Mass Atrocities After 1900

• Armenian Genocide (1915–1917): The Ottoman Turkish government systematically
deported and massacred its Armenian minority during WWI. Conservative
estimates are that some 600,000 to more than 1,000,000 Armenians were killed
during forced marches and killings. This event is widely recognized as one of the
first modern genocides.
• The Holocaust (1941–1945): Nazi Germany carried out the genocide of European
Jewry. Approximately six million Jewish men, women and children were murdered
 in concentration and extermination camps (Auschwitz, Treblinka, etc.) and mass
shootings. The Holocaust was the systematic state-sponsored killing of six million
Jewish men, women, and children and millions of others by Nazi Germany and its
collaborators. The “Final Solution” also targeted Roma, disabled persons, Poles,
Soviet POWs, and others. The Holocaust is the most infamous genocide of the era.
• Other 20th-Century Genocides: Several other mass killings occurred. In the 1930s,
Stalin’s regime caused a man-made famine (the Holodomor) in Ukraine, killing
millions (debated as genocide). Under Mao Zedong, the Great Leap Forward (1958–
62) led to a catastrophic famine with up to 30 million deaths. In Cambodia (1975–
79), the Khmer Rouge killed about 2 million people in the Cambodian Genocide. In
1994, the Rwandan Genocide saw an estimated 800,000 Tutsi (and moderate Hutu)
killed in 100 days. Each of these demonstrated the ideological ruthlessness of
regimes.
• Legacy – “Genocide” Defined: The magnitude of WWII atrocities led to the UN’s
1948 Genocide Convention, legally defining genocide. The Nuremberg Trials (1945–
46) prosecuted Nazi leaders for war crimes and crimes against humanity,
establishing that individuals and states could be held accountable for orchestrating
mass murder.

7.9 Causation in Global Conflict

• Multiple Factors: Global wars do not have a single cause. Historians emphasize
that social, political, economic and technological forces all interplay. For example,
new technologies (machine guns, artillery, bombs) changed warfare; long-term
imperial rivalries and power shifts (rising nations vs. declining empires) created
instability; and ideological conflicts (democracy vs. fascism vs. communism) drove
leaders’ ambitions. Economic crises and social upheavals (worldwide Depression,
revolutions) also contributed.
• Recurring Themes: Despite complexity, certain themes recur. World War I
reflected militarism, entangled alliances, imperial competition and nationalism
(“MAIN”). WWII was driven by some of the same forces plus ideological extremism:
fascist and expansionist regimes clashed with democracies and each other. In each
conflict, the causes build on earlier ones (WWI’s aftermath helped cause WWII, and
WWII’s power shifts led to Cold War and decolonization). The global conflicts of the
20th century thenarose from a web of interconnected causes – from economic
collapse to aggressive ideology – rather than a single trigger.
Key Terms: Nationalism; imperialism; militarism; alliances; self-determination; total war;
fascism; appeasement; genocide; League of Nations/United Nations; Lend-Lease; nuclear
weapons; decolonization.

Examples: Trench warfare, the Treaty of Versailles, the Great Depression/New Deal, Nazi
invasions, D-Day, the Holocaust, Hiroshima, UN Charter, Indian independence (1947).