Zimmerman Telegram and War
For Americans who remained reluctant to enter the war in Europe, the final straw came in the form of a telegram. In February 1917, the British government intercepted a message from German Secretary of War Arthur Zimmerman to the German Ambassador in Mexico. This message offered Mexico an alliance—if Mexico agreed to invade the United States, Germany promised to grant Arizona, New Mexico, and Texas to Mexico after war’s end.
Having received word of this German plot from the British, and amidst unrestricted U-boat attacks on domestic vessels, the United States finally declared war on Germany on April 6, 1917. The nation’s decision to enter the conflict was not, however, backed by the budget needed to supply the required material and human resources.