One of the reasons that caused America to declare war on Germany was Germany’s use of unrestricted submarine warfare. Germany’s inability to achieve success on land and on the sea versus Britain caused them to resort to unrestricted submarine warfare (Murphy132). On February 18, 1915, Germany’s announcement of attacking any commerce ships that were trading with Britain enraged America (Murphy140). This act from Germany became the starting point of provoking America to enter into World War One. America feared for the safety of their commerce ships that were trading with Britain. On May 7, 1915, began a series of events that provokes the United States to enter World War One; the British liner Lusitania was sunk by a German U-boat, killing more than one hundred Americans (Murphy148). This event outraged America, but not to the extent of declaring war on Germany until the channel streamer Sussex was torpedoed