Subscribe to BBC News to BBC News HERE decrypted German telegram intended for Mexico pushed the Unite An intercepted telegram between Germany and Mexico led the United States to declare war. Created by Sal Khan.Watch the next lesson: The Zimmermann telegram (or Zimmermann note or Zimmermann cable) was a secret diplomatic communication issued from the German Foreign Office in January 1917 that proposed a military contract between the German Empire and Mexico if the United States entered World War I against Germany. With Germany's aid, Mexico would recover Texas, Arizona, and New Mexico. The Zimmermann Telegram, a secret message from Germany to Mexico during the First World War, ended the United States' neutrality and sealed the fate of the C The British cryptographic office known as "Room 40" decoded the Zimmermann Telegram and handed it over to the United States in late-February 1917. By March 1, its scandalous contents were The American press published news of the telegram on March 1. On April 6, 1917, the United States Congress formally declared war on Germany and its allies. The Zimmermann Telegram had such an impact on American opinion that, according to David Kahn, author of The Codebreakers, "No other single cryptanalysis has had such enormous consequences." With this in mind, on January 16, 1917, Zimmermann's office handed their coded telegram off to the U.S. ambassador to Germany, James Gerard. Oblivious to its content, he dutifully wired it to August 20, 2012. On January 17, 1917, British code breakers in Room 40, the cryptoanalysis office of Great Britain's Naval Intelligence, intercepted a telegram from Germany. At first, they Zimmermann Telegram, coded telegram sent January 16, 1917, by German foreign secretary Arthur Zimmermann to the German minister in Mexico. The note revealed a plan to renew unrestricted submarine warfare and to form an alliance with Mexico and Japan if the United States declared war on Germany. The message was intercepted by

the British and The Zim­mermann Telegram. On Jan­uary 17, 1917 British signals intelligence intercepted and decrypted a coded German telegram from German Foreign Secretary Arthur Zimmermann that was intended for Germany's ambassador to Mexico. Though the United States was not yet a participant in the war, Zimmermann signaled Germany's intention to