What finally led to the US participation in World War 1?

The United States' participation in World War I was primarily triggered by a combination of factors, including unrestricted submarine warfare by Germany, which resulted in the sinking of civilian ships like the Lusitania, and the interception of the Zimmermann Telegram, in which Germany proposed a military alliance with Mexico against the US. These events, alongside growing economic ties to the Allies and a desire to protect American interests, ultimately swayed public opinion and led President Woodrow Wilson to ask Congress for a declaration of war in April 1917.