What Prompted American Entry into World War I?

The sinking of the Lusitania by Germany on May 7, 1915 prompted American entry into World War I. The Lusitania was a British passenger ship that was used to ship war materials. Secretary of State Bryan put Britain's shameful act perfectly: It was "like putting women and children in front of an army" (Davidson 671). Germany suspected the Lusitania contained war supplies so they, like any other intelligent nation would have, used a torpedo to ship the Lusitania. In February 1916, Germany then declared the use of submarines to attack ships regardless of whether they were neutral or not. This made complete sense, at least to the Germans, as Britain had a blockade which "reduced American contraband commerce with the Central Powers to a trickle" (Davidson 670). Unfortunately, U.S. President Wilson issued an ultimatum to Germany which stated that the U.S. would end diplomatic relations with Germany if they did not stop attacking neutral ships. Like most ultimatums, it would fail. Germany, wanting American goods and access to the Atlantic, resumed unrestricted attacks and the U.S. eventually declared war on Germany.

Another reason the U.S. went to war was the use of propaganda. Propaganda was used to gain American support for war against Germany. Americans saw Germany as an imperial nation (which of course is hypocritical since the U.S. basically did the same thing to Native Americans): "Americans read British propaganda about spike-helmeted "Huns" raping Belgian women, bayoneting their children, pillaging their towns" (Davidson 670). The Zimmerman telegram proved to be just as useful to those who wanted to go to war with Germany. The U.S., once again, handled the situation perfectly. They responded by ordering "gun crews aboard merchant ships and [directing] them to shoot U-boats on sight" (Davidson 672). And guess what the response was by Germany? Yes, of course, they attacked: "by the end of [March] U-boats had sunk nearly 600,000 tons of Allied and neutral shipping" (Davidson 672). The war was officially on shortly after, in spite of Wilson's campaign promises to "Keep Us Out of War" (Davidson 672).

Davidson, James, Brian Delay, Christine Heyrman, Mark Lytle, and Michael Stoff, Nation of Nations: A Narrative History of the American Republic Volume II: Since 1865. New York: McGraw-Hill, 2008.