The Telegram
On the 16th of January, 1917, the German Foreign Minister Arthur Zimmermann sent a telegram to Heinrich von Eckhardt, the German Ambassador to Mexico.[1]
"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.[2]
The original coded telegram Bernstorff forwarded to Eckhardt.[5]
German Foreign Minister Arthur Zimmermann[4]
First, the telegram noted of the German's plan to resume unrestricted submarine warfare. It then offered Mexico financial and military support to declare war on the United States to reclaim Texas, New Mexico, and Arizona.[1] It also suggested to ask Japan to enter the war, "detaching her from the European Allies to join the German-Mexican Alliance".[3]
However, the telegram was not sent directly to Mexico. It first was sent to Count Bernstorff, the Germany Ambassador to the United States. Bernstorff then forwarded the telegram to the German Minister in the Mexican Republic.[3] Zimmermann had to send the telegram this way because the United States and Germany had been discussing negotiated peace,[4] so sending the telegram to the United States first would not raise British suspicion.
The German Plan
Article in the newspaper about 4 ships that were sunk on Feburary 1, 1917.
Columbus Evening Dispatch
At this time in the war, the Germans and the British were both struggling against one another. The German High Command knew the allies depended on the United Sates. Americans supported Britain's war effort for "almost $10 million a day," by supplying artillery shells and 15,000 rifles daily.[1] The German military leaders believed that they could still win the war by cutting off British supplies with their U-boats* to starve Britain into surrendering within a few months.[3] "If that supply line could be severed, or America distracted, Germany could triumph."[1] Then Arthur Zimmermann promised he could embroil the U.S. in a war with Mexico.[3] A war with Mexico would mean the U.S. would be distracted and the Germans could cut off supplies easier.
* U-Boats were the German submarines.

The Failure
Count von Bernstorff, the German ambassador for the United States.
firstworldwar.com
Zimmermann's proposal to Mexico failed in two different ways. First, the message was not only sent by this telegram. It was also sent 2 different ways. One by letter from Nauen, Germany, to Sayville, Long Island, and the other by Swedish diplomatic agents.[3] The Sayville route was known as the "main line" to the British because it was the most direct and most used for sending German dispatches to the United States.[3] The British watched this route regularly and picked up on the message soon after it was sent. A similar event happened with Sweden's relay. The British knew that Sweden was pro German and were sending documents for them. The British intercepted it on its way to Buenos Aires from Stockholm, Sweden.[2] Second, using Bernstorff as the middle man made it easy for the United States government to find the telegram to show its authenticity. All the United States had to do was look for the original telegram in the Washington cable office and decode it with the key the British gave them.
The consequence of Zimmermann's failure to secure a route to Mexico directly increased his chances of the British picking up his message, decoding it, and letting the United States know. If Zimmermann had thought of a more secure route to Mexico, the United States may not have joined the war if Mexico declined Zimmermann's proposal.
[1] "Failed Diplomacy: the Zimmermann Telegram."
[2] "Transcript of Zimmermann Telegram."
[3] The Life and Letters of Walter H. Page.
[4] The Zimmerman Telegram.
[5] "Die Zukunft Des Internet Und Die Verborgene Geschichte Der Codebrecher."

Last updated Sunday, April 10, 2011 at 10:51PM.