Which factor contributed to the entry of the US into World War 1?

One significant factor that contributed to the entry of the U.S. into World War I was the unrestricted submarine warfare conducted by Germany, which threatened American commercial shipping and lives. The sinking of the Lusitania in 1915, where American passengers were killed, heightened public outrage. Additionally, the interception of the Zimmermann Telegram, in which Germany proposed a military alliance with Mexico against the U.S., further galvanized American support for entering the war. These provocations shifted public opinion and government policy towards involvement in the conflict.