The Zimmermann Telegram
Between 1914 and the spring of 1917, the European nations engaged in a conflict that became known as World War I. While armies moved across the face of Europe, the United States remained neutral. In 1916 Woodrow Wilson was elected President for a second term, largely because of the slogan "He kept us out of war." Events in early 1917 would change that hope. In frustration over the effective British naval blockade, in February Germany broke its pledge to limit submarine warfare. In response to the breaking of the Sussex pledge, the United States severed diplomatic relations with Germany.
In January of 1917, British cryptographers deciphered a telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, von Eckhardt, offering United States territory to Mexico in return for joining the German cause. This message helped draw the United States into the war and thus changed the course of history. The 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." It is his opinion that "never before or since has so much turned upon the solution of a secret message." In an effort to protect their intelligence from detection and to capitalize on growing anti-German sentiment in the United States, the British waited until February 24 to present the telegram to Woodrow Wilson. 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 story of British intelligence efforts to decipher the German code is fascinating and complicated. The Zimmermann Telegram by Barbara Tuchman recounts that story in all of its exciting detail. It is an excellent historical account for high school students.
The coded telegram is from Decimal File 862.20212/82A (1910-1929), and the decoded telegram below is from Decimal File 862.20212/69 (1910-1929), General Records of the Department of State, Record Group 59.
FROM 2nd from London # 5747.
"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.
[You can display JPEG images of the coded or decoded versions of the original document. The coded telegram is signed "Bernstorff" because it was transmitted through the United States and Bernstorff was the German ambassador in Washington.]
1. Decoding a Message: In this exercise, you will decode a fictitious message using a simple substitution code. You are to decipher message using the code, and then write down the decoded message.
2. What geographical advantages would the Germans gain by Mexican entry into the war? What was the role of Japan?
3. Further Analysis:
a. What other documents have changed the course of American history? For
example, consider the effects of the Emancipation Proclamation, the Monroe
Doctrine, and the Roosevelt Corollary.
b. What events in 1916 and 1917 contributed to the impact the Zimmermann
telegram would have on the American public?
c. Would the United States have remained neutral if the Zimmermann telegram had
not been revealed?