2. U.S Declares War Section 2

3. German Sub Warfare (U-boat) German subs broke the stalemate at the sea’s U-boats were used to sink allied supply ships 1915 U-boat sinks the Lusitania, a passenger liner. 1,200 passengers died, including 128 Americans Sussex Pledge – Germany was to warn before u- boat attacks

4. Lusitania Carried 4,200,000 rifle rounds 18 cases of explosive fuses

5. Zimmerman Note Intercepted by Britain The note was from Germany secretly asking Mexico to declare war on the U.S If Mexico declared war on U.S. Germany promised Mexico land in the U.S

6. America at War March 16, 1917 Germany sinks 3 American ships April 6, 1917 the president signs a resolution to go to war The resolution was supported strongly by senators and congressmen

7. Gas Warfare Chlorine Gas 1 st used by Germans Greenish yellow cloud Once inhaled brought on choking attacks as gas ate respiratory organs Mixes with mucus to produce hydrochloric acid (lethal) Phosgene Caused less coughing than chlorine gas Onset of symptoms came within 48 hours Can cause death b/c people don’t know they are exposed

8. Mustard Gas Odorless chemical Caused blisters internally and externally Would remain in soil for weeks If a trench was being lost armies would intentionally infect the trench