What was one of the main causes for the outbreak of World War One from the U.S. perspective?

One of the main causes for the outbreak of World War One from the U.S. perspective was Germany interfering with American freedom of the seas. Prior to the U.S. entry into the war, Germany implemented a policy of unrestricted submarine warfare, targeting vessels in the war zone, which included ships flying the American flag. This directly threatened American trade and safety at sea, as numerous American ships were sunk without warning, leading to loss of American lives and property.

The killing of civilians and disruptions to international trade heightened tensions between the United States and Germany, compelling the U.S. government and public opinion to shift toward supporting entry into the conflict. Events such as the sinking of the Lusitania, which resulted in significant American casualties, further galvanized anti-German sentiment and illuminated the dangers posed to U.S. interests by Germany's maritime policies. As such, this issue of maintaining freedom of the seas and protecting American lives and commerce played a critical role in the U.S. decision to join the war.