World War I/United States

First World War Back Course Overview · Lesson 1 - Introduction · Lesson 2 - "Europe explodes" - The crisis which lead to World War I · Lesson 3 - 1914 - The alliances and their agenda · Lesson 4 - The "Schlieffen Plan" - First weeks of war · Lesson 5 - The Eastern Front · Lesson 6 - Inventions during World War I and their effects · Lesson 7 - War at Sea · Lesson 8 - The United States in World War I · Lesson 9 - The Russian Revolution · Lesson 10 - 1918 - The end of war · Lesson 11 - The Treaty of Versailles · Lesson 12 - The importance of World War I in the History of the 20th Century · Lesson 13 - Conclusion · Lesson 14 - U.S. Foreign Policy after WWI Next

Reasons for U.S. Involvement in World War I

• German submarine warfare; especially the sinking of the Lusitania by a German U-boat.
• The United States had economic and political ties to Great Britain
• The Zimmerman Telegram
• Inability to remain neutral

Zimmerman Telegram

The Zimmerman Telegram was sent from Germany to Mexico in 1917. It asked Mexico to join the Central Powers and attack the United States. Mexico refused to attack the U.S., but when the U.S. found out about the Zimmerman Telegram, it angered Americans and led to the U.S. declaring war on Germany.

Lusitania Sinking

The RMS Lusitania

The RMS Lusitania was a British ocean liner that was sunk by a torpedo from a German U-boat in 1915. 128 Americans on board were killed. This event angered many Americans, but the U.S. would remain neutral until Woodrow Wilson led the nation to war in 1917.