1. The United States enters WWI!
Causes and Effects

2. Reasons for the United States entering WWI: The Sinking of the Lusitania
Unrestricted Submarine Warfare
Germany was attacking merchant ships to prevent goods from getting to Britain.
This would at times result in the deaths of American citizens.
Germans did this because America was shipping supplies to Great Britain.

3. The Lusitania
May 1915: German submarines sink a British passenger ship named the Lusitania.
Killed 128 American citizens
Germany states that the ship was carrying weapons.
Germany attempts to strike a deal with the U.S., stating that U-boats will surface and allow neutral passengers to evacuate.

5. Reasons for the United States entering WWI: Cultural Ties
Ties to Britain and France
Many Americans felt that they shared a culture with Britain because of sharing a language.
Many also felt connected to France as another democracy of the world.

6. Ties To Central Powers Ties to the Central Powers
Many American citizens were themselves immigrants or descendants of immigrants from Germany.
Many Irish Americans supported a war against Great Britain. Why?
Historically, the British have been viewed as oppressors by the Irish.
Many Russian immigrants in the United States left Russia due to the poor conditions there, and they felt those were brought on by the czar

7. Reasons for the United States entering WWI: The Zimmerman Note
1917: British intercept a note from German foreign minister Arthur Zimmerman to the Mexican government.
This note promised them that if the U.S. entered the war, Germany would aid Mexico in getting land back from the U.S. (New Mexico, Texas) in return for Mexico fighting the U.S.
The note was sent to the American government and made public.
This intensified American animosity towards Germany.