1. The United States Declares War

2. Key Terms U-boat Sussex pledge Zimmermann note Russian Revolution

3. German Submarine Warfare The use of German submarine warfare frustrated many Americans – Called U-boats New weapon that changed the rules of naval warfare Battle of Jutland tried to break the stalemate of Germans and the British – Passenger and merchant ships had no defense against the submarine

4. Sinking of the Lusitania May 7, 1915 is when a U-boat sighted the Lusitania – Wilson demanded that Germany stop its submarine warfare U-boats continued to torpedo Allied ships Sussex Pledge was a promise that U-boats would warn ships before attacking

5. Moving Toward War Wilson ran for reelection on the slogan “He kept us out of war” Germany went against the Sussex pledge – On February 3, the United States broke off diplomatic relations with Germany Wilson then asked Congress for permission to arm American merchant ships Zimmerman note was intercepted – Germany made a secret offer to Mexico Mexico would get land in America if they would attack America

6. Revolution in Russia and the War Resolution Russia had already suffered enormous casualties in the war – Czar Nicholas II was forced to give up the throne Monarchy was replaced by a republic Called the Russian Revolution Germans sank three US ships in three days – War resolution passed 82 to 6 Wilson signed it on April 6, 1917

7. Questions to Consider What was the naval battle called between the British and the Germans? What is the Zimmerman Note? Why was the sinking of the Lusitania not a good reason to go to war? http://www.history.com/topics/world-war- i/videos#u-boats-sink-the-lusitania-in-1915 http://www.history.com/topics/world-war- i/videos#u-boats-sink-the-lusitania-in-1915 http://www.history.com/topics/world-war- i/videos#world-war-i-germans-attack-us-navy- boats http://www.history.com/topics/world-war- i/videos#world-war-i-germans-attack-us-navy- boats