The 20th century reshaped the United States more profoundly than any previous era. From 1901 to 2000, America moved from an industrial nation grappling with internal reform to a dominant global power, shaped by world wars, economic crises, social movements, and technological revolutions. This century witnessed the rise of federal authority, mass consumer culture, civil rights struggles, Cold War rivalry, and rapid scientific advancement. This hub offers a concise overview of the major themes and turning points of 20th Century America, providing essential context and pathways to in-depth articles across the era.

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The Progressive Era (c. 1901–1917)

At the start of the century, Americans confronted problems tied to industrial growth: political corruption, unsafe working conditions, monopolies, and poverty in crowded cities. Reformers—often called Progressives—pushed for government action to regulate business and improve public life.

Key reforms included antitrust enforcement, food and drug regulation, labor protections, and democratic changes such as primary elections and direct election of senators. The era also helped build new federal capacity, including the Federal Reserve System (1913), which reshaped national economic policy.

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The United States in World War I (1917–1918)

The United States entered World War I in 1917 after rising tensions at sea and worsening relations with Germany. American troops and industrial production helped strengthen the Allied war effort in the final phase of the conflict.

At home, the war accelerated federal power, mobilized industry, and intensified debates about civil liberties and national identity—marking a major step toward America’s expanded international role.

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The Roaring Twenties (1920–1929)

The 1920s brought dramatic cultural and economic change. Mass production and advertising spread consumer goods such as cars, radios, and household appliances, while cities grew and popular culture expanded through film, music, and national media.

The decade also revealed deep tensions—between urban and rural values, modern lifestyles and traditional norms, and rising prosperity alongside economic fragility. That fragility became clear when the stock market crashed in 1929, ending the boom.

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Prohibition (1920–1933)

Prohibition was one of the era’s defining social experiments. The 18th Amendment and Volstead Act banned the manufacture and sale of alcohol nationwide, aiming to improve morality and public order.

Instead, Prohibition fueled bootlegging, organized crime, and widespread defiance of the law. Public opposition grew, and the policy was repealed by the 21st Amendment in 1933—showing how difficult it can be to enforce sweeping moral reform through legislation.

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The Great Depression and the New Deal (1929–late 1930s)

The Great Depression was the most severe economic crisis in modern American history. Bank failures, collapsing demand, and mass unemployment devastated families and communities across the country.

In response, Franklin D. Roosevelt’s New Deal expanded the federal government’s role through relief programs, job creation, banking reforms, and new regulations. The era permanently changed expectations about what government should do during national emergencies.

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The United States in World War II (1941–1945)

After remaining neutral early in the conflict, the United States entered World War II following Japan’s attack on Pearl Harbor in 1941. American industrial output and military power became decisive in the defeat of Nazi Germany and Imperial Japan.

The war ended with the use of atomic weapons against Hiroshima and Nagasaki and launched the United States into a new position of global leadership—along with new global responsibilities and fears.

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Cold War America (1945–1991)

After World War II, the United States and the Soviet Union became rival superpowers. They competed through alliances, espionage, propaganda, and proxy conflicts rather than direct war, shaping global politics for decades.

The Cold War influenced American defense spending, domestic politics, education, and culture—while major flashpoints abroad reinforced the idea that international events could directly affect life at home.

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The Civil Rights Movement (1950s–1960s)

One of the most important domestic transformations of the century was the fight against segregation and discrimination. Activists used legal challenges, boycotts, marches, and civil disobedience to demand equal rights and protection under the law.

The movement led to landmark federal legislation, including the Civil Rights Act (1964) and Voting Rights Act (1965), reshaping American democracy and setting long-term struggles over equality and citizenship.

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Postwar Prosperity and Social Change (1945–1970s)

After World War II, many Americans experienced rising wages, suburban growth, and expanding consumer culture. At the same time, the era saw major change: youth culture, women’s activism, new immigration patterns, and debates about the direction of American society.

Prosperity was real—but uneven—and political conflict grew sharper as Americans argued over rights, war, and the limits of government power.

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The Space Race and Technological America

The Cold War competition extended beyond Earth. The Soviet launch of Sputnik (1957) shocked the United States and accelerated investment in science and education.

America’s moon landing in 1969 became a defining symbol of national capability, while late-century innovations—computing, satellites, and communications—helped shape the modern economy and daily life.

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America at Century’s End (1970s–2000)

The late 20th century brought economic restructuring, cultural debate, and shifting foreign policy priorities. The collapse of the Soviet Union in 1991 ended the Cold War and left the United States as the world’s dominant power.

By 2000, America’s influence was global—economically, militarily, and culturally—while unresolved issues around inequality, rights, and America’s role in the world continued into the next century.

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