The Zimmerman Telegram
In January 1917, the British intercepted a telegram being transmitted via a Berlin-Stockholm-Buenos Aires- Washington cable route¹. The coded message was from the German Foreign Minister, Arthur Zimmerman, to the German Ambassador to the United States, Johann A. von Bernstorff. The message was then to be re-coded and sent to the German Minister in Mexico, Heinrich J. F. von Eckhardt. The “Zimmerman Telegram”, as it became known, was given to the cryptanalysis bureau of British Admiralty, known as “Room 40”
Room 40, formally the “Intelligence Division 25 (ID 25)”², had obtained German naval code books that aided in the deciphering of many German diplomatic codes. When the encrypted Zimmerman Telegram arrived in Room 40 it was given to Reverend William Montgomery and Nigel de Grey. These two recognized immediately that they were looking at a level of encryption that indicated it was a high-level diplomatic communication. The first transmission from Zimmerman to von Bernstorff was in a new cryptographic system identified as 0075. Code breakers in Room 40 were not able to completely decipher this code yet. The second transmission however, from von Bernstorff to von Eckhardt was transmitted using an older code identified as 13040.
Montgomery and de Grey were more familiar with this code and were able to confirm their suspicions with chunks of text recovered. The two men continued to work and within two weeks were able to give the completely decrypted message to Admiral Sir William Hall, director of naval intelligence. The message was as follows:
“We intend to begin on the first of February unrestricted submarine warfare. We shall endeavor in spite of this to keep the United States of America neutral. In the event of this not succeeding, we make Mexico a proposal or alliance on the following basis: make war together, make peace together, generous financial support and an understanding on our part that Mexico is to reconquer the lost territory in Texas, New Mexico, and Arizona. The settlement in detail is left to you. You will inform the President of the above most secretly as soon as the outbreak of war with the United States of America is certain and add the suggestion that he should, on his own initiative, invite Japan to immediate adherence and at the same time mediate between Japan and ourselves. Please call the President's attention to the fact that the ruthless employment of our submarines now offers the prospect of compelling England in a few months to make peace.”
Signed, ZIMMERMANN
The British, not wanting to reveal to the Germany that they were incepting transmissions and were able to decipher them, waited until February 23, 1917 before presenting the American ambassador, Walter Page, with the telegram. Page then sent the information on to President Woodrow Wilson. The United States would eventually be brought into the conflict, and the Zimmerman Telegram is probably the most notable piece of cryptanalysis in history.
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Photostat of the Zimmerman Telegram as Received by the German Ambassador to Mexico, 01/19/1917; General Records of the Department of State, 1756 - 1979, Record Group 59; Civilian Records LICON, Textual Archives Services Division (NWCTC), National Archives at College Park, College Park, MD. [Online version on September 13, 2004, available through the online catalog at http://www.archives.gov/research_room/arc/]. |
