What was the main reason the United states entered world war 1?

The main reason the United States entered World War I was due to a combination of factors, primarily the unrestricted submarine warfare practiced by Germany, which threatened American ships and lives. The sinking of the Lusitania in 1915, along with the interception of the Zimmermann Telegram in early 1917, further inflamed public opinion against Germany. Additionally, economic ties to the Allied powers and a desire to promote democracy and stability in Europe played significant roles in the U.S. decision to join the conflict.