Introduction to World Wars and the Rise of Modern Autocracies (1900–1945)

By 1900 Europe dominated the globe, and with colonial interests abroad and prosperity at home, Europeans anticipated a bright future. But clouds were gathering. Rapid growth in Germany destabilized the continent’s balance of power and led European states into an arms race and a tense arrangement of defensive military alliances. In 1914 a Serbian nationalist assassinated the heir to the Austro-Hungarian throne to protest Austria-Hungary’s occupation of Bosnia. The killing propelled Europe’s alliances into mobilization, and suddenly the continent was engulfed by large-scale conflict—the First World War.

More than ten million soldiers perished in four years of combat, conducted with the terrifying force of new technologies like airplanes, poison gas, and automatic weapons. After what seemed like endless stalemate, the Allies (led by Britain, France, Italy, and the United States) gained a decisive advantage, leading to the end of the war in 1918. The victors carved new states out of the vanquished Austro-Hungarian and Ottoman Empires and ensured a punitive outcome for Germany.

In Russia, the war brought more than heavy losses of men—it unleashed a revolution that ended monarchist rule in 1917. The communist Bolsheviks, led by Vladimir Ilich Lenin (1870–1924), set out to radically transform Russian society. Absorbing other constituent states of the Russian Empire, they named the new government the Union of Soviet Socialist Republics, or Soviet Union.

Amid the social and economic unrest of the postwar years, other radical movements were making gains. One of them was fascism, a movement for strong, autocratic leadership. In Italy, Benito Mussolini (1883–1945) amassed such a following that when his supporters marched on Rome in 1922, the king appointed him prime minister.

The New York stock market crash of October 24, 1929, set off the worst economic crisis of modern times. The Great Depression put tens of millions out of work worldwide, with especially severe effects in Western Europe and North America. The Depression lasted for a decade and weakened the western democracies in their clash with the fascists, who were in the ascendancy.

Adopting Mussolini’s ideology and aggressive tactics, Adolf Hitler (1889–1945) built a powerful fascist movement in Germany with his National Socialist (or Nazi) party. Weeks after he became chancellor in January 1933, Hitler declared emergency powers which would never be revoked, banned all political parties but his own, and used a mixture of propaganda and violence to build a militarized police state he called the Third Reich.

Spain’s elected government fell to a right-wing military leader during that country’s brutal civil war of 1936–1939. Hitler moved aggressively to expand his Third Reich, capturing Austria, Czechoslovakia, and Lithuania before any major power issued a strong challenge. In Asia, Japan had grown into an expansionist military power, taking over Manchuria, then declaring all-out war on China in 1937.

When Germany invaded Poland on September 1, 1939, Britain and France declared war, launching World War II. In 1940 Japan joined Hitler and Mussolini’s “Axis” alliance. Japan’s 1941 attack on Pearl Harbor, Hawaii, drew the United States into the conflict. The Second World War killed far more people than its predecessor, including six million Jews killed in Nazi concentration camps. Adolf Hitler’s suicide on April 30, 1945, marked the Allied victory in Europe. That August, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki, killing tens of thousands of civilians instantly and prompting Japan’s surrender.