In revolutionizing war at sea, the submarine exerted a decisive influence on politics ashore, Germany's resort to unrestricted submarine warfare provoked American entry into World War I. The German Government's wager that strangling British seaborne communications would force Great Britain from the war, leaving France to bleed to death alone before American assistance arrived, proved to be a disastrous miscalculation.
"Weapans Development, War Planning and Policy,"
Naval War College Review: Vol. 37
, Article 8.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol37/iss3/8