We discussed the major causes of WWI: 1) Complex system of Alliances (Triple Alliance & Triple Entente), 2) Nationalism, 3) Militarism, 4) Imperialism, 5) Assassination of Archduke Franz Ferdinand. Germany's march across Belgium into France. Central Powers vs. the Allied Powers. Modern warfare included: trench warfare, machine guns, poison gas, armored tanks, U-boats (submarines), blimps, airplanes. We discussed the challenge posed to President Wilson, ending a long period of U.S. neutrality. Reasons for U.S. involvement: 1) propaganda, 2) Germany's use of unrestricted submarine warfare, 3) sinking of the Lusitania, 4) the Zimmerman Telegram, 5) Russian Revolution. U.S. enters WWI in April, 1917. It passes the Selective Service Act in May 1917. The draft is enforced and the U.S. quickly raises armed forces to deploy to Europe.