Library of Congress

On April 2, 1917, President Woodrow Wilson asked Congress to declare war against Germany, saying, “The world must be made safe for democracy.” Four days later, Congress voted overwhelmingly in favor of a war declaration.

The New York Times reported that the “United States virtually made its entrance into the war” with Wilson’s speech. “Before an audience that cheered him as he has never been cheered in the Capitol in his life, the President cast in the lot of American unreservedly with the Allies and declared for a war that must not end until the issue between autocracy and democracy has been fought out.”



Since the start of World War I in 1914, the United States sought to stay out of the conflict. In an August 1914 speech, Wilson issued a declaration of neutrality, saying, “The United States must be neutral in fact, as well as in name, during these days that are to try men’s souls. We must be impartial in thought, as well as action, must put a curb upon our sentiments, as well as upon every transaction that might be construed as a preference of one party to the struggle before another.”

The majority of Americans supported neutrality, though American businesses and manufacturers did business with warring countries, providing munitions, food and loans primarily to the Allied side.

Over the next two and a half years, the United States was gradually drawn into the war by factors including German submarine aggression. In 1915, a German U-boat torpedoed the RMS Lusitania, a British merchant ship that was likely carrying munitions, killing 128 Americans. Wilson threatened action against Germany, which pledged to end attacks on merchant ships, but the issue cropped up again in March 1916 with a German torpedo attack on the French-owned ferry Sussex. The Germans again made promises to leave passenger ships alone, but in January 1917 it announced a policy of unrestricted submarine warfare. This declaration prompted Wilson to break relations with Germany.

The U.S. decision to enter the war was also influenced by the Zimmerman Telegram, a missive sent by German Foreign Minister Arthur Zimmerman to Germany’s Mexican ambassador promising to help Mexico reclaim U.S. land in exchange for support in the war. The telegram was intercepted by the British and sent to the U.S. on Feb. 24, 1917.

The United States had avoided preparing for war. As a result, its military was small and ill-equipped for war. Wilson called the “immediate addition” of 500,000 men through a draft and the “organization and mobilization of all the material resources of the country to supply the materials of war.”

The first U.S. troops arrived in France in June 1917 and, by the spring of 1918, provided a significant fighting force for the Allies. The arrival of fresh U.S. troops was a key factor in breaking the stalemate that had developed between the beleaguered European troops, contributing to the end of the war on Nov. 11, 1918. In all, more than 4 million U.S. troops were mobilized during the war and more than 2 million served in Europe.

Connect to Today:

After the wars of the 20th century and the U.S. military invasions that marked the start of the 21st century, some Americans are war-weary. An October 2011 edition of The Times’ Room for Debate examined a possible rise in isolationist sentiment in the U.S. and its implications for party politics and the 2012 presidential election.

Do you think American voters are looking for less interventionist leaders? Why or why not? What are the advantages and disadvantages of playing a smaller role in the global arena?



Learn more about what happened in history on April 2»

Learn more about Historic Headlines and our collaboration with findingDulcinea »