Social Studies unit 5 By stu.EzellS@mishawaka.k12.in.us 1823 The Monroe Doctrine Period: 1914 to 1918 World War 1 1915 Germany told America to stay of British ships, as they could and would sink them 1917 Germany announced "unlimited submarine warfare" in the war zone. 1917 United States 1917 Russia left the war after its communist revolution 1917 The Espionage Apr 7, 1917 New York Journal 1918 The Sedition Act