On April 2, 1917, President Woodrow Wilson asks Congress to send U.S. troops into battle against Germany in World War I. In his address to Congress that day, Wilson lamented it is a fearful thing to lead this great peaceful people into war. Four days later, Congress obliged and declared war on Germany.

In February and March 1917, Germany, embroiled in war with Britain, France and Russia, increased its attacks on neutral shipping in the Atlantic and offered, in the form of the so-called Zimmermann Telegram, to help Mexico regain Texas, New Mexico and Arizona if it would join Germany in a war against the United States. The public outcry against Germany buoyed President Wilson in asking Congress to abandon America’s neutrality to make the world safe for democracy.

Wilson went on to lead what was at the time the largest war-mobilization effort in the country’s history. At first, Wilson asked only for volunteer soldiers, but soon realized voluntary enlistment would not raise a sufficient number of troops and signed the Selective Service Act in May 1917. The Selective Service Act required men between 21 and 35 years of age to register for the draft, increasing the size of the army from 200,000 troops to 4 million by the end of the war. One of the infantrymen who volunteered for active duty was future President Harry S. Truman.

In addition to raising troop strength, Wilson authorized a variety of programs in 1917 to mobilize the domestic war effort. He appointed an official propaganda group called the Committee on Public Information (CPI) to give speeches, publish pamphlets and create films that explained America’s role in the war and drummed up support for Wilson’s war-time policies. For example, the CPI’s representatives, known as four-minute men, traveled throughout the U.S. urging Americans to buy war bonds and conserve food. Wilson appointed future President Herbert Hoover to lead the Food Administration, which cleverly changed German terms, like hamburger and sauerkraut, to more American-sounding monikers, like liberty sandwich or liberty cabbage.

Wilson hoped to convince Americans to voluntarily support the war effort, but was not averse to passing legislation to suppress dissent. After entering the war, Wilson ordered the federal government to take over the strike-plagued railroad industry to eliminate the possibility of work stoppages and passed the Espionage Act aimed at silencing anti-war protestors and union organizers.

The influx of American troops, foodstuffs and financial support into the Great War contributed significantly to Germany’s surrender in November 1918. President Wilson led the American delegation to Paris for the negotiation of the Treaty of Versailles in June 1919, a controversial treaty—which was never ratified by Congress–that some historians claim successfully dismantled Germany’s war machine but contributed to the rise of German fascism and the outbreak of World War II. Wilson’s most enduring wartime policy remains his plan for a League of Nations, which, though unsuccessful, laid the foundation for the United Nations.