1. A MERICA E NTERS W ORLD W AR I Essential Questions: 1. What was Operational Plan 3? 2. How did the sinking of the Lusitania impact American involvement in WWI? 3. How did the Russian Revolution of 1917 impact American involvement in WWI?

2. O PERATIONAL P LAN 3 German plan to invade the U.S. Invasion of the United States was considered vital by many within Germany Included an attack on America's Eastern Seaboard with 60 ships and 100,000 men They planned to start off by shelling Manhattan and capturing Boston Operational Plan 3 was eventually shelved German leaders realized that the German Navy was not powerful enough to stand up to the US Navy

3. T HE L USITANIA A British luxury ocean liner She was torpedoed by a German U-boat on May 7, 1915 The ship sank in 18 minutes killing 1,198 of the people aboard, 128 were Americans The sinking turned public opinion in many countries against Germany Germans said the Lusitania was carrying ammunitions Was a major factor in the decision of the U.S. to enter the war in 1917

4. Z IMMERMAN N OTE Telegram from German foreign minister to German ambassador in Mexico Decoded by British cryptographers Instructed German Ambassador to propose an alliance Germany would help Mexico regain territories lost in Mexican-American War Texas, New Mexico, and Arizona Reauthorized start of unrestricted submarine warfare by Germany Telegram caused American outrage Lead to declaration of war against Germany

5. R USSIAN R EVOLUTION Events in Russia removed the last significant obstacle to direct U.S. involvement in WWI In March 1917 the oppressive Russian Monarchy was replaced with a representative government Supporters of American entry into WWI could now claim that this was a war of democracies against brutal monarchies On April 6, 1917 the U.S. entered the First World War