1917 February 24 The Zimmerman note, written by German Foreign Minister Arthur Zimmerman to the German Ambassador in Mexico, is turned over to President Wilson by British intelligence, who had earlier intercepted and decoded the message. The note indicates that if Germany and the United States were to go to war, Germany would seek an alliance with Mexico -- offering the Mexicans Texas, New Mexico, and Arizona in return for their efforts. The British had held onto the note, waiting until the most propitious moment to present it to Wilson. It now becomes one of the most important factors in leading him to declare war on Germany. (Tuchman I)