Which event and similar incidents drew the US into World War 1?

The primary event that drew the United States into World War I was the sinking of the British ocean liner RMS Lusitania by a German U-boat in May 1915, resulting in the deaths of 128 Americans. Additionally, the interception of the Zimmermann Telegram in early 1917, in which Germany proposed a military alliance with Mexico against the U.S., heightened tensions. These incidents, combined with ongoing unrestricted submarine warfare by Germany, ultimately led President Woodrow Wilson to ask Congress for a declaration of war in April 1917.