Course Hero Logo

World War I: 1914–1918



When World War I broke out in Europe in 1914, the conflict seemed far removed for most Americans. President Woodrow Wilson was hesitant to involve the United States in the overseas war and encouraged Americans to remain neutral. Over the next few years, this position of neutrality became harder to maintain. Germany seemed intent on provoking America into entering the Great War. The unjustifiable sinking of the British passenger ship Lusitania, which carried American citizens, was followed by a revelation that Germany was conspiring with Mexico to invade the United States. With support of the American public, Congress at last declared war on Germany, and the United States entered World War I on April 6, 1917.

At A Glance

  • A complex system of international alliances and the assassination of Archduke Franz Ferdinand of Austria-Hungary by a Serbian national on June 28, 1914, led to a conflict that quickly spread across Europe and became known as World War I.
  • Wilson's 1914 Declaration of Neutrality was intended to keep the United States out of the conflict in Europe, a position most Americans supported at the time.
  • The loss of American lives in the sinking of British ocean liner Lusitania on May 7, 1915, helped turn public opinion against Germany and the Central Powers, moving the United States closer to entering the war in Europe.
  • The Zimmermann Telegram, intercepted and decoded by the British in January 1917, detailed German plans to offer Mexico territory in the American Southwest in exchange for a Mexican ground invasion of the United States.
  • The United States declared war on Germany on April 6, 1917, and moved quickly to mobilize troops to send overseas and to muster a workforce to replace the men sent into battle.
  • The Committee on Public Information, founded on April 13, 1917, was created by Woodrow Wilson to garner support for the war.
  • The Espionage Act (1917) and the Sedition Act (1918) were passed by Congress to suppress dissension during the war.
  • The United States' entry into the war ended the stalemate and turned the tide in favor of the Allies.
  • On January 8, 1918, Woodrow Wilson addressed a joint session of Congress to present his Fourteen Points, a vision for peace following World War I.
  • The Treaty of Versailles, signed on June 28, 1919, ended World War I but set the stage for future international conflict.
  • Established in 1920, the League of Nations was an international organization proposed by the Allies at the Paris Peace Conference and intended to prevent future international conflicts.