In an attempt to contend with the British Navy, Germany began to produce a new weapon of war—the U-boat. U-boats, a common English abbreviation for the German word `Unterseeboot', were submarines. Unlike surface ships, U-boats, did not adhere to the traditional rules of engagement, which required raiders to stop a vessel, examine its cargo, and allow passengers to escape before sinking the ship. Instead, the strength of the submarine was its ability to strike without warning, while its major weakness was its inability when surfaced to defend itself.

Germany began attacking British and American vessels in the waters of the North Atlantic. In March of 1915, Germany sunk the British steamer Falaba, killing one American. In May, two more lives were lost when Germany sunk the American tanker Gulfight. In all, during the first months of 1915, German U-boats destroyed more than 90 ships.

Germany’s aggression reached a turning point in May of 1915. Americans reacted in disbelief when a German U-boat attacked the Lusitania, a British passenger liner that was traveling from New York to Liverpool, England. Nearly 1,200 persons were killed, including 128 Americans. Germany defended the sinking of the Lusitania by correctly asserting that the ship was transporting a large supply of small-arms ammunition. This fact did little to convince Americans that Germany was justified. While many openly called for war, President Woodrow Wilson remained cautious against any action that would bring America into the battle.

Instead, President Wilson began to make a series of diplomatic moves to persuade Germany to shift its tactics. Wilson issued a note, grudgingly signed by Secretary of State William Jennings Bryan, demanding that the Germans abandon unrestricted submarine warfare. Germany responded with an explanation of their military situation but not an apology for their warfare tactics, nor any indication that they were willing to change their strategy. About one month later, Wilson issued a second, more strongly worded note. This time, Bryan, rather than signing a letter that could provoke a war with Germany, resigned from his position.

In reaction to the storm of criticism and anger concerning the sinking of the Lusitania, the German government secretly ordered its military to avoid sinking defenseless passenger ships. However, in August of 1915, Germany sunk the Arabic, another British liner, killing two Americans. With Allied pressure mounting, the German government finally agreed publicly to not sink unarmed ships without warning.

Germany’s pledge proved to be temporary. Seven months after the sinking of the Arabic, a German U-boat sunk the Sussex, a French steamer. In response, Wilson issued the Sussex Ultimatum, a decree that said the U.S. would break diplomatic relations with Germany if German U-boats continued to sink unarmed vessels. Again, Germany signaled that they would not sink passenger vessels without warning. However, Germany’s latest reassurance came with one major stipulation: the United States would have to persuade the Allies to stop blockading commodities to Germany. Wilson accepted Germany’s pledge, but he did not accept the decree concerning the Allies.

On January 31, 1917, in an effort to end the military stalemate in Europe, Germany declared that it would wage unrestricted warfare against all shipping vessels, neutral or belligerent, in the war zone. Although Wilson broke diplomatic relations with Germany, he refused to ask Congress for a declaration of war, arguing that Germany had still not committed any “actual overt acts” that warranted a military response.

The “overt acts” that would bring America into the war came during the next two months with the sinking of four more unarmed American vessels. At about the same time, newspapers published an intercepted telegram from German Foreign Secretary Arthur Zimmerman that proposed a German-Mexican alliance. In return for supporting Germany, Mexico was to reclaim the Texas, New Mexico, and Arizona territories. This proposed alliance concerned all Americans and was particularly troublesome to those living in the southwestern United States. Wilson was forced to acknowledge that the worst-case scenario for America was coming to pass and continuing to manage the German threat was no longer an option.

On April 2, 1917, Wilson requested a declaration of war from Congress. Congress complied with only six senators and 50 representatives voting against the war resolution. In his war message, Wilson declared, “It is a fearful thing to lead this great peaceful people into war.” Nevertheless, the crisis of war would soon engulf the United States.

Copyright 2006 The Regents of the University of California and Monterey Institute for Technology and Education