

On May 4, 1916, the German Government had accepted these terms and conditions in what came to be known as the " Sussex pledge."īy January 1917, however, the situation in Germany had changed. Following the sinking of an unarmed French boat, the Sussex, in the English Channel in March 1916, Wilson had threatened to sever diplomatic relations with Germany, unless the German Government refrained from attacking all passenger ships, and allowed the crews of enemy merchant vessels to escape from their ships prior to any attack. Germany's resumption of submarine attacks on passenger and merchant ships in 1917 was the primary motivation behind Wilson's decision to lead the United States into World War I. The United States later declared war on Austria-Hungary on December 7, 1917. Senate voted in support of the measure to declare war on Germany. Wilson cited Germany's violation of its pledge to suspend unrestricted submarine warfare in the North Atlantic and the Mediterranean, and its attempts to entice Mexico into an alliance against the United States, as his reasons for declaring war. On April 2, 1917, President Woodrow Wilson went before a joint session of Congress to request a declaration of war against Germany.
