The United States' entry into World War I marked a pivotal moment in global history. Initially neutral, America faced mounting pressure to join the conflict as German aggression intensified. The sinking of the Lusitania and the Zimmermann Telegram were key events that swayed public opinion. President Wilson's decision to declare war in 1917 transformed the U.S. into a major player on the world stage. The nation mobilized its resources, implementing a draft and shifting to wartime production. American troops and supplies proved crucial in turning the tide for the Allied Powers.