In which year did the United States officially enter World War I?

The United States officially entered World War I in 1917, marking a significant turning point in the conflict. Prior to this year, the U.S. maintained a stance of neutrality despite the ongoing war in Europe, which began in 1914. However, several factors, including unrestricted submarine warfare by Germany and the Zimmerman Telegram, in which Germany sought to persuade Mexico to join the war against the United States, shifted public and governmental opinion in favor of entering the war. The formal declaration of war took place on April 6, 1917.

Understanding the context of the war's timeline helps clarify why this year is pivotal. The U.S. mobilized its military and economic resources, supporting the Allied Powers and contributing to major offensives that ultimately led to the war's conclusion in 1918. Recognizing the year of U.S. entry into the war is essential for understanding America's evolving role on the global stage and the impact of the conflict on subsequent U.S. foreign policy.