In the winter of 1916–1917 the United States was still officially neutral in Europe’s Great War, but the situation was changing. The German foreign minister, Arthur Zimmermann, sent a telegram effectively proposing an alliance with Mexico in case the United States entered World War I.
The turning over of the Zimmermann telegram to the U.S. government by the British government in February dramatically changed the course of World War I. The telegram would be one of the last factors leading the United States to enter the war.
Since its release to the U.S. government the document has on occasion been the subject of questions as to how it came into the British government’s possession, and why officials took so long after receiving it to turn it over to the United States. The popular suspicion is that the Zimmermann telegram was deliberately forged, and was part of a conspiracy to force the United States to enter the war.
Barbara Tuchman laid out what has become the traditional interpretation in her book on the subject. German concerns over the ability to maintain the neutral status of the United States and a belief that Britain would be forced out of the war quickly if restrictions were lifted on its submarine commanders’ ability to sink ships led the German imperial government to decide to take a gamble. It chose to return to unrestricted submarine warfare from 1 February 1917, even though it might bring the United States into the war.
In order to deal with the potential U.S. involvement in the war the German government convinced itself that potential German allies to the south and west could divert U.S. attention from the continent. The idea would be to convince Mexico, and hopefully Japan, to go to war with the United States and keep it occupied in its own backyard.
The history of U.S.–Mexican relations at the time gave the Germans reason to hope. In 1836 Texas gained its independence from Mexico and was then annexed by the United States in 1845.
Then in 1848 the United States gained possession of California and the western United States south of Oregon and west of Texas after defeating Mexico in the Mexican American War (1846–1848). More recently the United States had sent troops into Mexico in 1914 to occupy Vera Cruz and then again in 1916 to deal with bandits.
The German foreign minister, Arthur Zimmermann, sent a telegram on 16 January 1917 to the German ambassador to the United States for forwarding to the German ambassador in Mexico.
It explained the German position; although the message espoused a German desire to maintain U.S. neutrality during the Great War, if this failed it proposed as an alternative that Mexico assault the United States with German assistance.
In exchange for Mexican cooperation they would receive German financial assistance and the return of territories of the American southwest that had been lost: “Mexico is to re-conquer the lost territory in Texas, New Mexico, and Arizona” (Tuchman, 146).
The telegram was intercepted by the British and decoded over the next few weeks. When the document was finished the British had a tool to use to convince the United States of its need to enter the war, but they first had to hide the evidence of how they came into possession of the document, causing a delay in its transmission to the U.S. government.
The British need for security of their code-breaking operations led to a desire to find a second source; that source was a copy of the telegram sent from Washington to Mexico, which contained subtle but significant differences from the one to Washington the British were already working on.
On 24 February Walter Page, the U.S. ambassador to the United Kingdom, telegraphed the contents of the telegram to Washington. He also sent along an explanation of the British delay in turning over the information to the United States, namely their desire to protect their sources (Hendrick, 334).
The document became public on 1 March, after which a public uproar ensued with some Americans claiming the document was a fraud. They were convinced that the Allies, and particularly the British government, lied to the United States in order to convince the Americans to support them during the Great War.
This was a response to a traditional U.S. concern about the British dating back to the American Revolution, an idea that would after World War I be replaced by the “special relationship.” The popular suspicion was that the telegram was not sent by the Germans but was the creation of British intelligence who used it to convince Americans of the immediate German threat to the United States.
This theory withered away quickly on 2 March when Zimmermann admitted having sent the telegram. Even with this, America’s entrance into the war was not immediate, as Wilson did not ask Congress for a declaration of war against Germany until 2 April and it was not passed by Congress until 6 April.
More recently it has been proposed that the Zimmermann telegram and the Balfour declaration were tied together. In a letter of 2 November 1917 British Foreign Secretary Arthur Balfour stated the government’s support for the establishment of a “national home for the Jewish people” in Palestine; this has since come to be known as the Balfour declaration. John Cornelius has argued that the declaration was the price for the un-encoded text of the Zimmermann telegram.
He argued that it was unlikely that the British were capable of breaking the German diplomatic code (or else the Germans would not have used it), and thus the information about the contents must have come from another source. He argued that Zionists in Germany worked with Zionists in Britain to make a deal in which the British would get the text of the telegram in exchange for the acknowledgment of their rights in Palestine.
This theory assumes that since the Germans used a code they believed unbroken, it must have been unbroken, and thus the British needed help from German Zionists to get the contents of the telegram. British success in breaking the German Enigma code in World War II suggests the weakness of this logic. It is also based on a timetable of events that though interwoven, does not show any direct connection between the actions.
The ultimate impact of the Zimmermann telegram is unknown. As Tuchman noted, it was likely that at some point Germany would push the United States into the war. And while the theory of a relationship between the Zimmermann telegram and the Balfour declaration is potentially interesting for its impact in the Middle East, the theory does not answer as many of the questions about either document as the proponents believe.