Zimmerman Telegram 311.
(photo credit: US National Archives)
On March 1, 1917, a secret diplomatic cable that would alter the course of World War I and inevitably of modern history was published for public consumption. The Zimmerman Telegram was a cable from German Foreign Secretary Arthur Zimmerman to Germany’s ambassador in Mexico, containing instructions for a proposed Mexican-German alliance in case the United States eventually entered WWI. Although the telegram was not the sole catalyst that brought the US into “the war to end all wars,” it was the last straw in a series of events that eventually led to hundreds of thousands of American troops being shipped across the Atlantic.
In the first years of WWI, the United States was resolutely uninterested
in involving itself in foreign wars. Still largely guided by the Monroe
Doctrine, which forbade on principle European intervention in the
Western Hemisphere and vice versa, the US was opposed to any involvement
in internal European affairs. Although vexed by German submarine
warfare in the Atlantic, the Sussex Pledge of 1916, in which Germany
promised to restrict its naval attacks, sufficiently placated the United
States, ensuring its neutrality in the war.
RELATED:This Week in History: IAF shoots down Libyan Flight 114This Week in History: The capture of Eli Cohen
In early 1917, however, the German Empire reneged on the Sussex Pledge
and reinstituted its tactic of unrestricted submarine warfare. Less than
a month before resuming its attacks on merchant and passenger ships,
the German foreign minister began preparing for the likelihood that such
a move might push the US into the war; Zimmerman sent a cable to his
ambassador in Mexico with instructions to make a bold offer to the
If and when the United States entered WWI, the ambassador was to offer
financial support and backing for a Mexican declaration of war against
the US. In an alliance Zimmerman described as “make war together, make
peace together,” the Germans promised that Mexico would be given its
lost territories of Texas, Arizona and New Mexico at the end of the war.
Additionally, Mexico would be asked to enlist Japan into the German
alliance. The coded telegram was meant to reach only the German
ambassador to Mexico but only a few weeks later, would be read by
millions and significantly contribute to the deflating German defeat.
On January 17, British intelligence intercepted a German telegram
ciphered using a brand new code that they could not break. In a twist of
fate, Zimmerman’s embassy in Mexico had not yet received the new code
being used by Germany. The telegram had to be deciphered at the German
embassy in Washington and then relayed once again in a code that both
its Mexican mission (and the British) could understand. Finally able to
decipher it, the British immediately recognized the impact the cable
could have on America’s readiness to join the war. More than a month,
however, would pass before Britain shared the explosive cable with US
President Woodrow Wilson.
Wary of exposing their signal intelligence capabilities to the Germans,
the British waited until they were able to acquire a slightly altered,
Mexican version of the cable before presenting it to the Americans. By
doing so, they successfully convinced Germany that the telegram was
leaked by an embassy employee in Mexico and not, as was actually the
case, intercepted and deciphered. On February 23, 1917, the Zimmerman
Telegram was presented to the US ambassador in London, who passed it
along to the US president two days later.
On March 1, 1917, then-president Wilson decided to release the Zimmerman
Telegram for publication in the news media. The American public and
many media outlets initially suspected that the telegram was a British
forgery intended to draw the US into the war. Their suspicions were put
to rest several days later when Zimmerman himself gave a speech,
personally verifying the authenticity of the telegram bearing his name.
Faced with mounting casualties of unrestricted submarine warfare and
incontrovertible evidence of German intentions to intervene on the North
American continent, Woodrow Wilson asked Congress to declare war on
Germany. The United States and Germany were officially at war four days
Both Mexico and Japan immediately rejected the offers contained in the
Zimmerman cable and therefore, there was never any real threat posed to
the United States by the cable. However, just the idea that a European
power was willing to incite and support Mexico in a war against the US,
quickly led to Washington’s entrance into WWI. In this context and
considering the effect that American participation had on the outcome of
WWI, the Zimmerman Telegram – quite possibly the first Wikileak – was
perhaps the most consequential of any compromised diplomatic cable in
(coded version of the Zimmerman Telegram)
(decoded version of the Zimmerman Telegram)