One development after 1914 brought a direct confrontation between the
governments in Berlin and Washington: the German use of submarine warfare.
Americans expected to be able to trade and travel in wartime under the
protection of neutrality. Submarine warfare placed American lives in the line
of fire, and the inevitable crisis with Berlin soon arrived. When a German
submarine sank the British liner Lusitania on May 7, 1915, killing 128
Americans, the United States took a direct diplomatic part in the war.
American pressure forced Germany to limit its use of the submarine, and the
United States now assumed the role of a potential adversary if Germany's
leaders renewed the submarine campaign of early 1915. Earlier frictions and
irritations with Britain had arisen over American trade with the continent. The
British navy, for example, diverted or detained American ships bound for
Scandinavian ports to make sure they were not carrying strategic goods that
could be sent on to Germany. Such concerns now faded. Americans distinguished
between the minor irritations of British restrictions on the shipment
of goods and the German willingness to take American lives.
World History
