1. The United States in World War I
“Oh, no you di-int!”

2. Isolationism
The United States foreign policy between the American Civil War and World War I was one of isolationism
Non-involvement in the actions of decisions of other nations of the world
Particularly not getting trapped in European entanglements
A time of great economic and political prosperity for the nation
Rapidly growing economy
Industrial revolution
Growth into a world power

3. United States Neutrality
Most people in American supported the Allied Cause, and thought the Central Powers the aggressors in the conflict
Allies: Great Britain, France, Serbia, Russia
Central Powers: Austria-Hungary, Germany
American sentiment was divided in some areas
Irish Americans did not want to aide Great Britain, whom the considered an oppressor of their home land
German Americans did not want to go to war against their own homeland
President Wilson was firm in his resolve to have the United States remain neutral

4. President Woodrow Wilson
Staunch anti-involvement policy
Maintain business relationships with both sides
Didn’t want to anger any groups of Americans by choosing sides.
Used his platform as a powerful world leader to try and broker peace
Each side in the conflict was so certain of victory, Wilson’s peace proposals were ignored

5. Sinking of RMS Lusitania
RMS Lusitania was a British trans-Atlantic passenger liner
Passenger ships were initially protected from U-Boat Warfare
The Allies began to use passenger ships to carry weapons and ammunition since they couldn’t be torpedoed
The RMS Lusitania

6. Sinking of the RMS Lusitania
Lusitania was torpedoed on May 7, 1915 by the German U-Boat U20
The British were arming passenger vessels in order to lure U-Boats to the surface to attack them
U-Boats then began to sink everything
Passengers were warned to board at their own risk
On board the Lusitania were 128 American citizens
The wreckage of the RMS Lusitania beneath 300 feet of water off the coast of Ireland

8. Reaction
1198 people were killed, including the 128 American passengers
American citizens were outraged, and anti-German sentiment began to grow
President Wilson wanted the United States to remain neutral in spite of the attack
“America is too proud to fight”
Wilson warned the Germans that further unrestricted submarine warfare will not be tolerated
Germans halted unrestricted submarine warfare in response to international pressure… for now…

9. German Foreign Secretary Arthur Zimmerman
The Zimmerman Note
A telegram sent to the German Ambassador to Mexico Heinrich von Eckhardt by German Foreign Secretary Arthur Zimmerman
The telegram contained the command to arrange an agreement with Mexico
In return for Mexico’s declaration of war against the United States, Germany would return Texas, Arizona, New Mexico, and parts of California to Mexico
von Eckhardt was left to sort out the details
German Foreign Secretary Arthur Zimmerman

10. The Zimmerman Note
Left: The original telegram sent to the German Ambassador to Mexico
Right: The British cryptologists begin the process of decoding

11. The Zimmerman Note
The Zimmerman Note decoded

12. Mexico’s New Territory
Mexican Territory ceded to the United States after the War of 1850
Land promised by Germany for a Mexican declaration of war on the U.S.
Mexico

13. Achtung! Dies ist ein Skandal! Das ist nicht gut!
The British were able to decode the message, and soon presented it to the United States Ambassador to Great Britain
Ambassador Walter Page was first incredulous, and then enraged
President Wilson was then informed, and he released the text to the American people
American opinion rapidly changed to favor the Allies
A confident Zimmerman, when presented with the evidence, did not deny the arrangement
Poor relations between Mexico and the United States also contributed to Americans’ anger
The Germans now found themselves with an angry United States as a potential enemy

14. The United States has no choice
War is declared after the resumption of unrestricted U-Boat Warfare
The Germans were warned after the sinking of the Lusitania
The Zimmerman offer was tremendous insult, and could never have worked
The Mexicans didn’t believe that the Germans could pay up
There was no upside in declaring war on America
The United States officially enters The Great War on the side of the Allies on April 6, 1917
General John J. “Black Jack” Pershing, Commander of all U.S. Forces in World War I