Zimmermann Telegram (or Zimmermann
Note; ; ) was a coded
telegram dispatched by the Foreign
Secretary of the German
Zimmermann, on January 16, 1917, to the German ambassador in Washington, Johann
von Bernstorff, at the height of World
War I. On January 19,
Bernstorff, per Zimmermann's request, forwarded the Telegram to the
German ambassador in Mexico, Heinrich von Eckardt.
The Zimmermann Telegram as it was sent
from Washington to Mexico
sent the Telegram in anticipation of the
resumption of unrestricted submarine warfare
by the German
Empire on February 1
, an act which German
would draw the neutral United States into war on the side of the
. The Telegram
instructed Ambassador Eckardt that if the United States appeared
likely to enter the war he was to approach the Mexican government
with a proposal for military
. He was to offer Mexico material aid in the
reclamation of territory lost during the Mexican-American War, specifically the
American states of Texas, New Mexico, and Arizona.
was also instructed to urge Mexico to help broker an alliance
between Germany and Japan.
The Zimmermann Telegram was intercepted and decoded by the British
cryptographers of Room
. The revelation of its contents in the American press on
caused public outrage that
contributed to the United States' declaration of war against
Germany and its allies on April 6
Zimmermann's message was :
On the first of February, we intend to begin
unrestricted submarine warfare. In spite of this, it is our
intention to endeavor to keep the United States of America
In the event of this not succeeding, we propose an alliance on the
following basis with Mexico: That we shall make war together and
make peace together. We shall give generous financial support, and
an understanding on our part that Mexico is to reconquer the lost
territory in New Mexico, Texas, and Arizona. The details of
settlement are left to you.
You are instructed to inform the President [of Mexico] of the above
in the greatest confidence as soon as it is certain that there will
be an outbreak of war with the United States and suggest that the
President, on his own initiative, invite Japan to immediate
adherence with this plan; at the same time, offer to mediate
between Japan and ourselves.
Please call to the attention of the President that the ruthless
employment of our submarines now offers the prospect of compelling
England to make peace in a few months.
Mexican President Venustiano
assigned a general to assess the feasibility of a
Mexican takeover of their former territories . The general
concluded that it would not be possible or even desirable for the
- Attempting to re-take the former territories would mean certain
war with the United States.
- No matter how "generous" it was, Germany's "financial support"
would be worthless. Mexico could not use it to acquire arms,
ammunition, or other war supplies, because the United States was
the only sizable arms manufacturer in the
Americas. The Royal Navy controlled
the Atlantic sea lanes, so Germany could not possibly supply any
quantity of arms.
- Even if Mexico had the military means to re-take the territory
it would have had severe difficulty accommodating and/or pacifying
the large English-speaking population.
- Mexico had even cooperated with the ABC
nations to prevent a war with the United States, generally
improving relations. If Mexico were to enter war against USA it
would strain relations with ABC nationsâ€”who would later declare war
Carranza formally declined Zimmermann's proposals on April 14
, by which time the U.S. had declared war
The Telegram was transmitted by radio and also across two telegraph
routes under the cover of diplomatic messages by two neutral
governments, Sweden and the United States. Germany lacked direct
telegraphic access to the Western hemisphere because the British
had cut the German cables in the Atlantic and shut down German
stations in neutral countries. This forced Germany to use British
and American cables instead despite the risk of interception. The
Zimmermann messages passed over cables that touched on British
soil, and as a result were intercepted there by British
intelligence. President Woodrow Wilson had granted the German
diplomats the privilege of sending their messages under the cover
of U.S. diplomatic traffic in hopes that this would enable Germany
to remain in touch with the United States and further Wilson's aims
of ending the war. The message passing through this way was sent
from Berlin to the
German ambassador in Washington, Johann von Bernstorff,
for re-transmission to von Eckardt in Mexico.
What was a
privilege provided to further peace actually brought war.
The Telegram was intercepted as soon as it was sent. The
codebreakers in Room 40
at the Admiralty
received a copyand decrypted
enough to get the gist of it. The
German Foreign Office encrypted the Telegram with cipher 0075,
which Room 40 had partly broken.
The British government wanted to use the incriminating Telegram. It
provided a splendid opportunity to draw the United States into
World War I on the Allied side. Anti-German feeling in the United
States was particularly strong at that moment, due to the German
policy of "unrestricted" submarine
But the British had two problems. They had to explain to the
Americans how they got the ciphertext of the Telegram, without
telling the Americans about the British intelligence operation
monitoring neutral diplomatic traffic, and they had to have a
public explanation of how they had the Telegram's deciphered text
without revealing to Germany that they had broken German
The British solved the first problem by also getting the ciphertext
of the Telegram from the telegraph office in Mexico. The British
guessed that the German Embassy in Washington would relay the
message by commercial telegraph. So the Mexican telegraph office
would have the ciphertext. "Mr. H.", a British agent in Mexico,
bribed an employee of the commercial telegraph company for a copy
of the message. (Sir Thomas Hohler
then British ambassador in Mexico, claims to have been Mr. H in his
autobiography.) This ciphertext could be passed to the Americans
The retransmission was enciphered using cipher 13040, which Britain
had captured a copy of in Mesopotamia
. So by mid-February the
British had the complete text.
The second problem was solved by a cover story: that the Telegram's
deciphered text had been stolen in Mexico. (The U.S. was informed
of the deciphering, but backed up the cover story.) The German
government refused to consider a possible code break, and instead
sent von Eckardt on a witch-hunt for a traitor in the embassy in
The Telegram, completely decrypted and
British use of the Telegram
On February 19
, "Blinker" Hall
, the head of Room 40,
showed the Telegram to the secretary of the U.S. Embassy in
Britain, Edward Bell. Bell was at first incredulous, thinking it
was a forgery, then enraged. On February
Hall informally sent a copy to U.S. ambassador Walter Page
. On February 23
, Page met with Foreign Minister
, and was given the
ciphertext, the message in German, and the English translation.
Then Page reported the story to President Woodrow Wilson
, including details to be
verified from telegraph company files in the U.S.
Effect in the United States
Popular sentiment in the United States at that time was
anti-Mexican as well as anti-German, while Mexico was anti-American
and in some cases, anti-European. General John J. Pershing
had long been chasing the
revolutionary Pancho Villa
, who had
carried out several cross-border raids. News of the Telegram
further inflamed tensions between the U.S. and Mexico.
At first, the Telegram was widely believed to be a forgery
perpetrated by British intelligence. This belief, which was not
restricted to pacifist and pro-German lobbies, was promoted by
German and Mexican diplomats, and by some American papers,
especially the Hearst
empire. However, first on March 3, 1917 and later on March 29,
1917, Arthur Zimmermann himself admitted that the Telegram was
On February 1
, Germany had resumed
"unrestricted" submarine warfare, which caused many civilian
deaths, including American passengers on British ships. This caused
widespread anti-German sentiment. The Telegram greatly increased
this feeling. Besides the highly provocative anti-U.S. proposal to
Mexico, the Telegram also mentioned "ruthless employment of our
United States declares war against Germany
Wilson responded by asking Congress
to arm American ships
so that they could fend off potential German submarine attacks. A
few days later, on April 2, 1917, Wilson asked Congress to declare
war on Germany. On April 6, 1917, Congress complied, bringing the
United States into World War I.
The telegram was not the only reason for the U.S. entry into the
war. Previously, German U-boats had sunk US ships or ships which carried US
citizens, of which the most well known was the RMS Lusitania, torpedoed off the coast of Ireland in May
1915. US ships sunk, less well known, were the SS
Housatonic in Feb 1917 in
the Bay of
Biscay, and the SS California off the Irish
It was perceived as especially perfidious that the
Telegram was sent to the German embassy in Washington via the U.S.
embassy in Berlin and the U.S.-operated cable from Denmark (in
fact, that was the only relatively sure channel left to the Germans
to communicate to their diplomats in Mexico). Once the American
public believed the Telegram to be real, it was all but inevitable
that the U.S. would join the Great War.
2005, it was revealed that an original typescript of the deciphered
Zimmermann Telegram had recently been discovered by an unnamed
historian who was researching and preparing an official history of
the United Kingdomâ€™s Government
Communications Headquarters (GCHQ).
The document is believed to be the
actual telegram shown to the American ambassador in London in 1917.
Marked in Admiral Hall's handwriting at the top of the document are
the words: "This is the one handed to Dr Page and exposed by the
President." Since many of the secret documents in this incident had
been destroyed, it had previously been assumed that the original
typed "decrypt" was gone forever. However, after discovery of this
document, the GCHQ official historian said: "I believe that this is
indeed the same document that Balfour handed to Page."
- Beesly, Patrick (1982). Room 40: British Naval
Intelligence, 1914â€”1918, New York: Harcourt, Brace,
Jovanovich. ISBN 0-15-178634-8
- Bernstorff, Count Johann Heinrich (1920). My Three Years in
America, New York: Scribnerâ€™s. pp. 310-311.
- Friedman, William F., and Mendelsohn, Charles J.  (1994).
The Zimmermann Telegram of January 16 1917 and its
Cryptographic Background, Laguna Hills, CA: Aegean Park
- Hopkirk, Peter (1994). On
Secret Service East of Constantinople, Oxford University
Press. ISBN 0-19-280230-5
- Pommerin, Reiner (1996). "Reichstagsrede Zimmermanns (Auszug),
30. MÃ¤rz 1917", in: Quellen zu den deutsch-amerikanischen
Beziehungen, Darmstadt: Wissenschaftliche Buchgesellschaft.
Vol. 1, pp. 213-216.
- Singh, Simon The Zimmermann Telegram
- Tuchman, Barbara W. (1958).
The Zimmermann Telegram, Ballantine Books. ISBN
- West, Nigel (1986). The SIGINT Secrets, William Morrow & Co/Quill.
- London Daily Telegraph, 17 October 2005. " Telegram that brought US into Great War is
Found". Article by Ben Fenton.
- Massie, Robert K. (2004).
Castles of Steel, Vantage Books, London, 2007. ISBN
- Further reading
- Dugdale, Blanche (1937). Arthur James Balfour, New
York: Putnamâ€™s. Vol. II, pp. 127-9.
- Hendrick, Burton J.  (July 2003). The Life and
Letters of Walter H. Page, Kessinger Publishing. ISBN
- Kahn, David  (1996). The Codebreakers, New York:
- Katz, Friedrich (1981). The Secret War in Mexico,
University of Chicago Press. ISBN 0-226-42589-4
- Link, Arthur S. (1965) Wilson, Vol. 5,
Princeton, NJ: Princeton University Press. Pages 433-5.
- Winkler, Jonathan Reed (2008) "Nexus: Strategic Communications
and American Security in World War I," Cambridge, MA: Harvard
University Press. ISBN 978-0674028395
- Massie, Robert K., Castles of Steel, pp.516-18, 527,
542, 548, 714.
- http://www.simonsingh.com/Zimmermann_Telegram.html Room 40
Larger image of the telegram
Perception of the Telegram in the U.S.
- Timeline of WW1