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 ships carrying civilians and goods to the Allies. The sinking of ships such as the Lusitania, along with Germany’s renewed submarine campaign in 1917, helped turn U.S. opinion against Germany and contributed to the United States entering the war on the Allied side. Therefore, the main result was that it helped bring the United States into the war.

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