1. World War I: Factors leading to U.S. involvement in WWI

2. Unrestricted Submarine Warfare Unrestricted Submarine Warfare: The German navy vowed to sink any ship without warning in British waters which resulted in the sinking of five American ships- and the deaths of over 100 American citizens. Unrestricted Submarine Warfare: The German navy vowed to sink any ship without warning in British waters which resulted in the sinking of five American ships- and the deaths of over 100 American citizens.

4. The Zimmerman Note The telegram asked for Mexico to join the Central Powers in the war and in exchange Germany would help Mexico regain territory lost to the U.S. (New Mexico, Texas, Arizona etc.) The telegram asked for Mexico to join the Central Powers in the war and in exchange Germany would help Mexico regain territory lost to the U.S. (New Mexico, Texas, Arizona etc.)

6. Other Factors… U.S. ultimately sides with the British and Allied Forces due to a common ancestry, language, and similar styles of government. U.S. ultimately sides with the British and Allied Forces due to a common ancestry, language, and similar styles of government.