The United States officially entered World War I on April 6, 1917, after a prolonged period of neutrality. Rising tensions over unrestricted submarine warfare practiced by Germany, particularly the sinking of the RMS Lusitania and the interception of the Zimmermann Telegram, fueled public outrage and pressured the U.S. government to act. President Woodrow Wilson sought to maintain peace but ultimately advocated for intervention to protect American interests and promote democracy. The U.S. entry provided a much-needed boost to Allied forces, contributing to the eventual defeat of the Central Powers and altering the course of the war significantly.