The Zimmerman Telegram

The Zimmerman Telegram was a secret message sent in 1917 by Germany to Mexico, proposing they form an alliance against the United States during World War I. Germany promised Mexico territory lost to the U.S. if they joined the war. British spies intercepted and decoded the message, then shared it with the U.S., which caused outrage. The revelation helped sway American public opinion to support entering the war against Germany. The telegram exemplified the use of diplomatic deception and had significant impact on the course of the war and U.S. foreign policy.