What is the Zimmerman note and what was the reaction of the Americans?

The Zimmermann Note was a secret diplomatic communication sent by German Foreign Minister Arthur Zimmermann to Mexico in January 1917, proposing a military alliance against the United States in the event that the U.S. entered World War I. The note promised Mexico the territories of Texas, New Mexico, and Arizona as a reward for joining the Germans. When the British intercepted and revealed the note to the U.S., it incited public outrage and fueled anti-German sentiment, contributing significantly to America's decision to enter the war. The revelation of the note played a crucial role in galvanizing American support for intervention against Germany.