04 World War I and Its Aftermath

From neutrality to war

When war began in Europe in 1914, President Woodrow Wilson declared that the United States would remain neutral. Despite this policy, American trade and financial ties with the Allied powers grew, while German submarine warfare increasingly threatened American shipping.

In early 1917, Germany resumed unrestricted submarine warfare. News of the Zimmermann Telegram, in which Germany proposed an alliance with Mexico, further inflamed public opinion. Wilson asked Congress to declare war, and the United States declared war on Germany on April 6, 1917.

The United States entered the war late, but its troops and supplies strengthened the Allies. The American Expeditionary Forces, commanded by General John J. Pershing, fought in major campaigns in 1918. An armistice ended the fighting on November 11, 1918.

Mobilizing the nation

Waging the war required a rapid expansion of federal power and national production. The Selective Service Act of 1917 established conscription: more than 24 million men registered, and draftees made up most of the U.S. Army.

Federal agencies coordinated production, transportation, fuel, and food. Led by Herbert Hoover, the Food Administration urged people to conserve voluntarily. The government financed the war through taxes and bond campaigns, while the Committee on Public Information promoted support through speeches, posters, and other publicity.

Mobilization also changed American society. Women entered some industrial jobs that had previously been less accessible to them, although many wartime opportunities diminished after the fighting. Wartime factory jobs and reduced European immigration accelerated the Great Migration, as African Americans moved from the rural South to northern and western cities. They faced discrimination in their new communities, and racial violence erupted in several cities in 1919.

Dissent and civil liberties

Efforts to promote public unity did not end opposition to the war, the draft, or particular government policies. Socialists, pacifists, labor activists, and conscientious objectors were among those who protested.

The Espionage Act of 1917 and Sedition Act of 1918 were used to prosecute people accused of obstructing the war effort or criticizing the government. Socialist leader Eugene V. Debs was imprisoned after giving an antiwar speech. These laws and prosecutions sharply restricted political expression and raised enduring questions about civil liberties during wartime.

The peace settlement

In January 1918, Wilson announced his Fourteen Points as a proposed basis for peace. They included national self-determination, arms reduction, and a League of Nations intended to prevent future wars.

At the 1919 Paris Peace Conference, the victorious Allies negotiated the Treaty of Versailles. It imposed territorial losses and reparations on Germany and established the League of Nations.

The treaty became a central political dispute in the United States. Some senators rejected membership in the League altogether. Others, led by Henry Cabot Lodge, demanded reservations to protect Congress’s authority and the nation’s freedom of action. Wilson opposed those reservations.

The Senate rejected the treaty in votes in November 1919 and March 1920, so the United States never joined the League. In 1921, the United States formally ended its state of war with Germany and concluded a separate peace treaty.

The war’s aftermath

World War I drew the United States into a European conflict and transformed the federal government’s role in military service, production, and public life. Mobilization created new opportunities while intensifying racial migration and restricting dissent. After the armistice, disagreement over the Treaty of Versailles and the League of Nations kept the United States outside the postwar organization Wilson had championed.