What event triggered the US to get involved in the great war?

The United States was prompted to enter World War I primarily due to the unrestricted submarine warfare conducted by Germany, which threatened American shipping and lives. The sinking of the British ocean liner RMS Lusitania in 1915, resulting in the deaths of 128 Americans, heightened tensions. Additionally, the interception of the Zimmermann Telegram in early 1917, in which Germany proposed a military alliance with Mexico against the U.S., further galvanized public and political support for intervention. As a result, the U.S. declared war on Germany on April 6, 1917.