The United States Declares War

Key Terms

• U-boat• Sussex pledge• Zimmermann note• Russian Revolution

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

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

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

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

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/vi

deos#u-boats-sink-the-lusitania-in-1915• http://www.history.com/topics/world-war-i/vi

deos#world-war-i-germans-attack-us-navy-boats