What 2 German actions caused the US to enter world war l?

Two key German actions that prompted the U.S. to enter World War I were unrestricted submarine warfare and the Zimmermann Telegram. The German navy's policy of sinking ships without warning, including those carrying American passengers, angered the U.S. Additionally, the Zimmermann Telegram, in which Germany proposed a military alliance with Mexico against the U.S., further inflamed American public opinion and pushed the U.S. toward war. These actions contributed significantly to the U.S. decision to join the Allies in 1917.