Chapter Notes: The Twentieth Century

The twentieth century was one of the most dramatic and transformative periods in human history. During this century, the world experienced two devastating global wars that reshaped borders, governments, and daily life for millions of people. New technologies changed how people fought wars, communicated, and understood their place in the world. The century began with optimism and progress, but quickly descended into conflict as nations competed for power, resources, and influence. Understanding the first half of the twentieth century-especially the two World Wars-helps us see how the modern world took shape and why international cooperation became so important.

World War I: The Road to War

In the early 1900s, Europe seemed peaceful and prosperous on the surface, but beneath this calm exterior, tensions were building that would eventually explode into the first truly global war. Several long-term causes created a dangerous situation where a single event could trigger a massive conflict involving dozens of nations.

Nationalism and Competition

Nationalism is a strong feeling of pride and loyalty to one's nation, often accompanied by the belief that one's country is superior to others. In the decades before World War I, nationalism grew increasingly intense across Europe. Countries competed fiercely with one another for territory, prestige, and influence. This competition created jealousy and mistrust between nations.

In particular, several regions experienced nationalist tensions:

• The Balkans: This region in southeastern Europe was known as the "powder keg of Europe" because many different ethnic groups lived there under the control of larger empires, especially Austria-Hungary and the Ottoman Empire. Slavic peoples in this region wanted independence and their own nations.
• Germany: After unifying in 1871, Germany rapidly industrialized and sought to become a major world power, challenging Britain and France's dominance.
• France: The French remained bitter about losing the Franco-Prussian War in 1871 and wanted to regain territory taken by Germany, especially the regions of Alsace and Lorraine.

Imperialism and Colonial Rivalry

Imperialism is the policy of extending a nation's power by gaining control over other territories and peoples, often to acquire resources and markets. By 1914, European powers had carved up most of Africa and large parts of Asia into colonies. This scramble for colonies created serious rivalries, particularly between:

• Britain and Germany over colonial territory in Africa
• France and Germany over Morocco in North Africa
• Russia and Austria-Hungary over influence in the Balkans

Each colonial crisis increased tensions and made European powers more suspicious of one another's intentions.

Militarism

Militarism refers to the glorification of military power and the policy of maintaining a strong military and being prepared to use it aggressively. In the years before 1914, European nations engaged in an intense arms race, building up their armies and navies to unprecedented sizes. Germany and Britain competed to build the most powerful navy, while Germany, France, and Russia expanded their armies and developed detailed war plans.

This military buildup had two dangerous effects. First, it made countries more confident about going to war because they believed their militaries could win quickly. Second, it created pressure to use these massive armies before they became obsolete or before rival nations gained an advantage.

Alliance Systems

To protect themselves and gain strength, European nations formed two major alliance systems. An alliance is an agreement between nations to support each other, especially during war. By 1914, Europe was divided into two armed camps:

These alliances were supposed to prevent war by making potential aggressors think twice-if you attacked one nation, you would face all of its allies. However, the alliance system actually made war more likely because a conflict between any two nations could quickly drag all their allies into the fight, turning a small dispute into a massive war.

The Spark: Assassination at Sarajevo

On June 28, 1914, Archduke Franz Ferdinand, heir to the throne of Austria-Hungary, visited Sarajevo, the capital of Bosnia. Bosnia had recently been annexed by Austria-Hungary, but many Bosnian Serbs wanted to be part of Serbia instead. A Serbian nationalist named Gavrilo Princip, who belonged to a secret organization called the Black Hand, shot and killed Franz Ferdinand and his wife Sophie.

Austria-Hungary blamed the Serbian government for supporting the assassination. With Germany's backing, Austria-Hungary issued an ultimatum-a final set of demands-to Serbia. When Serbia rejected some of these demands, Austria-Hungary declared war on July 28, 1914.

The alliance system immediately activated like a row of falling dominoes:

1. Russia mobilized its army to support fellow Slavic nation Serbia
2. Germany declared war on Russia to support Austria-Hungary
3. France mobilized to support Russia
4. Germany declared war on France and invaded Belgium to reach France quickly
5. Britain declared war on Germany to defend Belgium and France

Within weeks, what began as a dispute between Austria-Hungary and Serbia had exploded into a continental war involving all the major European powers.

World War I: The Great War

World War I, which lasted from 1914 to 1918, was unlike any previous conflict in history. The combination of old military tactics and new industrial technology created unprecedented destruction and suffering. People at the time called it the "Great War" because they could not imagine a larger or more terrible conflict-though sadly, an even worse war would follow just two decades later.

New Technologies of Destruction

The Industrial Revolution had transformed how wars were fought. World War I introduced several new weapons and technologies that made the conflict especially deadly:

• Machine guns: These automatic weapons could fire hundreds of bullets per minute, making it almost impossible for soldiers to advance across open ground. A few soldiers with machine guns could hold off thousands of attacking troops.
• Artillery: Massive cannons fired explosive shells over long distances, destroying fortifications and creating enormous craters. Artillery caused more deaths than any other weapon in the war.
• Poison gas: Both sides used chemical weapons like chlorine and mustard gas, which caused blindness, burns, and choking death. Gas masks became essential equipment.
• Tanks: Introduced later in the war, these armored vehicles could cross trenches and barbed wire, though early models were slow and often broke down.
• Airplanes: Initially used for reconnaissance, aircraft eventually engaged in aerial combat and bombing raids, introducing a new dimension to warfare.
• Submarines: German U-boats (Unterseeboots) attacked merchant and military ships, threatening Britain's supply lines and eventually drawing the United States into the war.

Trench Warfare

The most distinctive feature of World War I was trench warfare, particularly on the Western Front in France and Belgium. When Germany's initial invasion of France stalled in 1914, both sides dug elaborate systems of trenches-deep ditches protected by barbed wire, sandbags, and machine gun positions.

Life in the trenches was miserable and dangerous. Soldiers faced:

• Constant threat from artillery bombardment and sniper fire
• Mud, rats, and lice in unsanitary conditions
• "Trench foot," a painful condition caused by standing in cold, wet conditions
• Psychological trauma from the constant stress and witnessing death

Imagine living in a muddy ditch for months at a time, unable to stand up without risking your life, sleeping while rats crawled over you, and watching your friends die beside you-this was the reality for millions of soldiers.

Periodically, commanders ordered soldiers to go "over the top"-to climb out of the trenches and charge across "no man's land" (the devastated area between opposing trenches) toward enemy positions. These attacks typically resulted in enormous casualties for minimal gains. Some battles saw hundreds of thousands of deaths for the capture of just a few miles of territory.

Major Battles and Fronts

World War I was fought on several fronts across Europe, the Middle East, and Africa. The most important battlegrounds included:

The Western Front

The Western Front stretched from the English Channel through Belgium and France. This front saw some of the war's most famous and deadly battles:

• Battle of the Marne (1914): France stopped Germany's initial invasion, leading to the development of trench warfare.
• Battle of Verdun (1916): Germany attacked French forces in the longest battle of the war, lasting ten months. Nearly 700,000 soldiers died or were wounded, with neither side gaining significant ground.
• Battle of the Somme (1916): British forces attacked German trenches, suffering 60,000 casualties on the first day alone-the bloodiest day in British military history. The entire battle caused over one million casualties.

The Eastern Front

The Eastern Front stretched from the Baltic Sea to the Black Sea, where Russian forces fought against Germany and Austria-Hungary. Fighting was more mobile here than in the west, with armies advancing and retreating over vast distances. Russia suffered enormous losses, with millions of soldiers killed, wounded, or captured. These defeats, combined with food shortages at home, contributed to the Russian Revolution in 1917.

The Global War

Although the heaviest fighting occurred in Europe, World War I truly was a global conflict. Fighting took place in:

• The Middle East: British forces fought the Ottoman Empire (which had joined the Central Powers) in Palestine and Mesopotamia (modern-day Iraq).
• Africa: Allied and German colonial forces fought for control of German colonies in Africa.
• The Atlantic Ocean: German submarines hunted merchant ships carrying supplies to Britain, while British naval forces blockaded German ports.
• Asia: Japan, which joined the Allies, seized German colonies in China and the Pacific.

The Home Front

The home front refers to civilian life during wartime. World War I required total war-the complete mobilization of a nation's resources, economy, and population toward the war effort. This affected civilians in several ways:

• Industrial production: Factories that once made consumer goods switched to producing weapons, ammunition, and military supplies.
• Rationing: Governments limited how much food, fuel, and other goods civilians could purchase to ensure supplies for the military.
• Women's roles: With millions of men in the military, women took jobs in factories, offices, and farms that had previously been closed to them. This experience contributed to the women's suffrage movement and changing social roles.
• Propaganda: Governments used posters, newspapers, and films to maintain public support for the war effort and encourage people to buy war bonds, conserve resources, and enlist in the military.

America Enters the War

When war began in 1914, the United States remained neutral. President Woodrow Wilson believed America should stay out of European conflicts, and many Americans agreed. However, several factors gradually pushed the United States toward war:

1. Economic ties: American banks and businesses had lent billions of dollars to Britain and France and sold them vast quantities of supplies. An Allied defeat would threaten American economic interests.
2. Submarine warfare: Germany's policy of unrestricted submarine warfare threatened American ships and lives. In 1915, a German submarine sank the passenger liner Lusitania, killing 128 Americans among 1,198 total casualties.
3. The Zimmermann Telegram: In 1917, British intelligence intercepted a secret message from German Foreign Minister Arthur Zimmermann to Mexico, proposing a German-Mexican alliance against the United States. When newspapers published this telegram, American public opinion turned strongly against Germany.
4. Russian Revolution: When Russia's czarist government fell and was temporarily replaced by a democratic government in early 1917, Wilson felt more comfortable joining a war that could be framed as a fight for democracy.

On April 6, 1917, Congress declared war on Germany. American entry into the war provided fresh troops, supplies, and financial resources that would eventually tip the balance in favor of the Allies.

World War I: Ending the War

By 1918, all the warring nations were exhausted. Millions had died, economies were strained to the breaking point, and populations at home faced food shortages and war weariness. Several developments in 1918 finally brought the war to a conclusion.

The Final Year

In early 1918, Germany faced both a crisis and an opportunity. Russia had withdrawn from the war after the Bolshevik Revolution of 1917, freeing up German troops from the Eastern Front. Germany launched a massive offensive on the Western Front in spring 1918, hoping to win before American forces arrived in large numbers.

The German offensive initially succeeded, pushing back Allied lines. However, the attack exhausted German resources and manpower. By summer 1918, American troops were arriving in France at the rate of 10,000 per day. In July, the Allies launched a counteroffensive that steadily pushed German forces back.

By autumn 1918, Germany's situation had become desperate:

• The British naval blockade had caused severe food shortages in Germany
• German allies Austria-Hungary, Ottoman Empire, and Bulgaria were collapsing
• German soldiers were exhausted and demoralized
• Revolution threatened at home as civilians demanded an end to the war

The Armistice

On November 11, 1918, at 11:00 a.m., an armistice-an agreement to stop fighting-went into effect. Germany agreed to withdraw its forces, surrender its weapons, and accept Allied occupation of German territory along the Rhine River. Kaiser Wilhelm II, Germany's emperor, had already fled to the Netherlands, and Germany became a republic. The guns finally fell silent after four years of devastating warfare.

The human cost of World War I was staggering:

In total, approximately 10 million soldiers died, with another 21 million wounded. Civilian deaths from military action, starvation, and disease added millions more to the toll.

The Treaty of Versailles

In 1919, representatives from the Allied powers met in Paris to negotiate peace treaties with the defeated Central Powers. The most important of these was the Treaty of Versailles with Germany. The treaty reflected the competing goals of the major Allied leaders:

• Woodrow Wilson (United States): Wanted a fair peace based on his Fourteen Points, which included self-determination for nations, freedom of the seas, and the creation of an international peacekeeping organization.
• Georges Clemenceau (France): Wanted harsh punishment for Germany to ensure it could never threaten France again.
• David Lloyd George (Britain): Wanted to maintain British power and satisfy demands for revenge without completely destroying Germany.

The final treaty was a compromise that satisfied no one completely. Its major provisions included:

1. War guilt clause: Germany had to accept complete responsibility for causing the war.
2. Reparations: Germany had to pay enormous financial payments to the Allies-eventually set at $33 billion-to compensate for war damages.
3. Territorial losses: Germany lost all its overseas colonies and significant European territory, including Alsace-Lorraine to France, territory to Poland, and territory to Denmark.
4. Military restrictions: Germany's army was limited to 100,000 soldiers, prohibited from having submarines or an air force, and forbidden from stationing troops in the Rhineland (the region along the French border).
5. League of Nations: Wilson's proposal for an international organization to prevent future wars was included in the treaty.

"The Allied and Associated Governments affirm and Germany accepts the responsibility of Germany and her allies for causing all the loss and damage to which the Allied and Associated Governments and their nationals have been subjected as a consequence of the war imposed upon them by the aggression of Germany and her allies." - Article 231 of the Treaty of Versailles (the "war guilt clause")

This clause forced Germany to accept sole blame for the war, which humiliated Germans and created lasting resentment. Many Germans felt the treaty was unfair and excessively harsh, particularly since they had not been defeated on their own soil and had expected a more moderate peace based on Wilson's Fourteen Points.

Problems with the Peace

The Treaty of Versailles and the other peace treaties created several problems that would contribute to future conflicts:

• German resentment: The harsh terms and war guilt clause created a desire for revenge in Germany that would later be exploited by Adolf Hitler and the Nazi Party.
• Economic instability: The enormous reparations payments crippled the German economy, contributing to hyperinflation and economic crisis in the 1920s.
• Redrawing borders: The treaties created new nations in Eastern Europe by breaking up Austria-Hungary and the Ottoman Empire, but the new borders often left ethnic minorities trapped in countries where they faced discrimination.
• Weakened League of Nations: The United States Senate refused to ratify the Treaty of Versailles, meaning the U.S. never joined the League of Nations. Without American participation, the League lacked the power to enforce its decisions effectively.
• Unresolved issues: The treaty punished Germany but did not address the underlying causes of the war, such as nationalism, imperialism, and competition for power.

World War II: The War Begins

Just twenty-one years after World War I ended, the world was plunged into an even more devastating conflict. World War II (1939-1945) would ultimately involve more nations, kill more people, and cause more destruction than any war in human history. Understanding how this war began requires examining the troubled period between the two world wars.

The Road to Another War

Several developments in the 1920s and 1930s created conditions for another global war:

The Great Depression

In 1929, the American stock market crashed, triggering a worldwide economic crisis called the Great Depression. Unemployment soared, businesses failed, and international trade collapsed. This economic catastrophe had important political consequences. Desperate people turned to extreme political movements that promised simple solutions to complex problems. In Germany, economic suffering helped Adolf Hitler and the Nazi Party gain power.

Rise of Totalitarian Regimes

Totalitarianism is a form of government in which the state controls all aspects of public and private life and does not tolerate opposition. During the 1920s and 1930s, totalitarian governments came to power in several countries:

• Soviet Union: After the Bolshevik Revolution, Vladimir Lenin and later Joseph Stalin established a communist dictatorship that controlled the economy and brutally suppressed all opposition.
• Italy: Benito Mussolini and his Fascist Party took power in 1922, promising to restore Italian greatness through aggressive nationalism and military expansion.
• Germany: Adolf Hitler and the Nazi Party gained power in 1933, establishing a fascist dictatorship based on extreme nationalism, racism, and the desire to overturn the Treaty of Versailles.
• Japan: Military leaders gained control of the Japanese government and pursued aggressive expansion in Asia to secure resources and territory for Japan's growing population.

Failure of the League of Nations

The League of Nations proved unable to prevent aggressive nations from violating international law. When Japan invaded Manchuria in 1931 and Italy invaded Ethiopia in 1935, the League issued protests but took no effective action. This weakness encouraged further aggression.

Hitler's Aggression

After becoming Germany's dictator in 1933, Adolf Hitler systematically violated the Treaty of Versailles and pursued an aggressive foreign policy aimed at expanding German territory:

1. Rearmament (1935): Hitler openly began rebuilding Germany's military, violating the treaty's restrictions. Britain and France protested but took no action.
2. Rhineland (1936): German troops marched into the Rhineland, which was supposed to remain demilitarized. Again, Britain and France did nothing.
3. Austria (1938): Hitler annexed Austria in the Anschluss (union), adding Austria's territory and resources to Germany.
4. Czechoslovakia (1938-1939): Hitler demanded that Czechoslovakia surrender the Sudetenland, a border region with many German-speaking people. At the Munich Conference in September 1938, Britain and France agreed to Hitler's demand, hoping to avoid war through a policy of appeasement-giving in to an aggressor's demands to maintain peace.

British Prime Minister Neville Chamberlain returned from Munich claiming to have achieved "peace for our time." However, appeasement failed completely. In March 1939, Hitler seized the rest of Czechoslovakia, proving his promises were worthless.

The Nazi-Soviet Pact

In August 1939, the world was shocked when Nazi Germany and the Soviet Union-bitter ideological enemies-signed a nonaggression pact, agreeing not to attack each other. Secretly, the two dictators also agreed to divide Poland between them. This pact removed Hitler's fear of fighting a two-front war and cleared the way for Germany to attack Poland.

Invasion of Poland

On September 1, 1939, German forces invaded Poland using a new military tactic called blitzkrieg ("lightning war"). Blitzkrieg combined fast-moving tanks, motorized infantry, and air power to overwhelm enemies quickly before they could organize effective resistance. Polish forces fought bravely but were outmatched by Germany's modern military.

This time, Britain and France had guaranteed Poland's independence. On September 3, 1939, both countries declared war on Germany. World War II had begun. Two weeks later, the Soviet Union invaded Poland from the east, and Poland was divided between the two totalitarian powers.

Early German Victories

After conquering Poland, Germany turned west in spring 1940. Using blitzkrieg tactics, German forces quickly conquered:

• Denmark and Norway (April 1940): Secured to protect German access to Swedish iron ore
• Netherlands, Belgium, and Luxembourg (May 1940): Conquered in days
• France (May-June 1940): German tanks bypassed France's defensive fortifications by driving through the Ardennes Forest, which the French had believed impassable. German forces reached the English Channel in just ten days, cutting off Allied armies. France surrendered in June 1940, just six weeks after the German invasion began.

The fall of France shocked the world. The French army, considered one of Europe's strongest, had been defeated in weeks. Germany now controlled most of Western Europe.

Battle of Britain

Britain now stood alone against Nazi Germany. Hitler planned Operation Sea Lion, an invasion of Britain, but first needed to gain control of the air. Beginning in summer 1940, the German air force (Luftwaffe) launched massive bombing raids against British airfields, factories, and cities.

The Battle of Britain was the first major battle fought entirely in the air. British pilots, flying Spitfire and Hurricane fighters, defended their homeland with extraordinary courage. British Prime Minister Winston Churchill rallied his nation with stirring speeches:

"We shall defend our island, whatever the cost may be. We shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender." - Winston Churchill, June 1940

By autumn 1940, the Luftwaffe had failed to achieve air superiority, and Hitler postponed the invasion of Britain indefinitely. Britain had survived, providing a base from which the Allies would eventually launch the liberation of Europe.

Expanding the War

While Germany dominated Europe, the war spread to other regions:

• North Africa: Italian and German forces fought British troops for control of North Africa and access to Middle Eastern oil.
• The Balkans: Germany invaded Yugoslavia and Greece in spring 1941, securing its southern flank.
• The Atlantic: German submarines attacked British shipping, trying to starve Britain into surrender.

In June 1941, Hitler made a fateful decision that would ultimately doom Nazi Germany: he invaded the Soviet Union, breaking the Nazi-Soviet Pact. Operation Barbarossa was the largest military invasion in history, involving three million German troops. Initially, German forces advanced rapidly, but the vast distances, harsh winter weather, and fierce Soviet resistance eventually stopped the German advance.

Meanwhile, in Asia, Japan continued its aggressive expansion, seeking to establish a "Greater East Asia Co-Prosperity Sphere" under Japanese control. Japan's need for resources, particularly oil, would soon bring it into conflict with the United States, transforming World War II into a truly global conflict.