Causes  Britain blockaded Germany. No military supplies were to enter – later included food. American merchants did not fight blockade Germans begin to starve. Germans use U-Boats (Unterseeboot) to combat blockade.  Unrestricted Submarine Warfare No Warning

Sinking of the Lusitania  Submarine sank British liner off the coast of Ireland. 1,198 people died – 128 Americans Germans stated the liner was carrying ammunition. Americans angered  Two more ships would be sunk by German ships against American Protest Arabic and Sussex German Promise of not attacking passenger ships is broken many times.

Last Straw  Wilson attempted to mediate the war after 1916 election. “Peace without victory”  Unrestricted Submarine Warfare. All ships in British Waters will be sunk.  British Agents intercepted Zimmermann Note. German Ambassador attempted to convince Mexico to attack us from the south. Germany would support Mexico in reclaiming Texas – should war break out with U.S.

Russian Revolution (Bolshevik) *When US enters in 1917, Russia had dropped out*  Russia 1917 had successful Bolshevik Revolution led by Vladimir Lenin Led to set up of Communism in Russia Result in Russia withdrawing from World War I Fear of losing war due to lack of Russian army

US Impact  US enters (April 1917) and helps turn the tide of war US fights many battles that push Germans out of France Battle of Marne- turning point of the war and an Allied victory November 1918 both Austria- Hungary and Germany will surrender November an armistice or cease- fire agreement is signed

Costs of World War I  22 million died- half of them civilians  20 million more wounded  10 million refugees- left without a home  US lost 48,000 men in battle and another 62,000 from disease  Additional 200,000 wounded or emotional shock (Shell shock)  Cost to US- $338 billion (mainly loans to other countries and equipment costs)  Cost countries like Germany and France much more due to destruction of buildings and towns