What was the main result of Germany’s use of unrestricted submarine warfare during World War I?

Germany’s unrestricted submarine warfare meant German submarines attacked ships without warning, including vessels carrying civilians and goods. These attacks angered the United States and helped lead it to declare war on Germany in 1917, joining the Allies. So the main result was that it helped push the United States into the war on the Allied side.

AI-written and checked against the verified answer.