--- title: Zimmermann Telegram at 100: This Message Changed History description: The infamous Zimmermann Telegram was given to President Woodrow Wilson 100 years ago, on Feb. 24, 1917. See the decoded document here. canonical: https://time.com/4673502/zimmermann-telegram-100/ author: Lily Rothman article:opinion: false article:content_tier: free article:published_time: 2017-02-23T17:03:44.000Z article:modified_time: 2026-05-11T04:59:03.741Z article:section: History og:title: Here's How the Decoded Zimmermann Telegram Changed History og:description: The infamous Zimmermann Telegram was given to President Woodrow Wilson on Feb. 24, 1917 og:url: https://time.com/4673502/zimmermann-telegram-100/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production og:image:width: 1200 og:image:height: 675 og:image:alt: TIME og:type: article twitter:card: summary_large_image twitter:title: Here's How the Decoded Zimmermann Telegram Changed History twitter:description: The infamous Zimmermann Telegram was given to President Woodrow Wilson on Feb. 24, 1917 twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production --- # The Zimmermann Telegram at 100: This Decoded Message Changed History  by [Lily Rothman](https://time.com/author/lily-rothman/)  ## Lily Rothman Rothman is managing editor at TIME. Feb 23, 2017 5:03 PM UTC  by [Lily Rothman](https://time.com/author/lily-rothman/)  ## Lily Rothman Rothman is managing editor at TIME. Feb 23, 2017 5:03 PM UTC Exactly a century ago this Friday, on the morning of Feb. 24, 1917, the office of U.S. Secretary of State Robert Lansing received a telegram of warning from the U.S. Ambassador to Britain. In roughly three hours, the ambassador wrote, he would send another telegram, meant for Lansing and President Woodrow Wilson. It was going to be something important. When the second telegram arrived, it bore news that would play a role in changing the course of the next 100 years: the ambassador was telling the U.S. that he had received from the British the decoded text of a message they had intercepted from the Foreign Minister of Germany, Arthur Zimmermann, to his country’s minister to Mexico. At the time, the U.S. remained neutral as the Great War raged across Europe. Although many Americans saw it becoming inevitable that their nation would eventually join the fight, those who favored staying out of it could still make an argument that what was going on was none of America’s business. After all, an ocean separated the U.S. from the fighting and, though attacks by German submarines on [ships making the Atlantic crossing](http://time.com/3840371/lusitania-100-years/) had earlier galvanized those who favored war, German authorities had [agreed](http://www.history.com/this-day-in-history/germany-agrees-to-limit-its-submarine-warfare) in 1916 to limit attacks on non-military ships. But the information in the telegram intercepted by the British told the President that the time had come. “Among the official cryptograms which have been intercepted and translated by governmental authorities other than those for whom they were intended, the most important of all time, either in war or peace, is undoubtedly the one deciphered by the British Naval Intelligence which is known to historians as the _Zimmermann telegram_,” declared [a 1938 War Department ](https://www.nsa.gov/news-features/declassified-documents/friedman-documents/assets/files/lectures-speeches/FOLDER%5F198/41766889080599.pdf)report, which has since been declassified. The chilling text of the document, as [transcribed](https://www.ourdocuments.gov/doc.php?doc=60&page=transcript) in the National Archives, was as follows: --- > “” ---  Zimmermann Telegram Decimal File, left, and decoded Zimmermann Telegram, 1917. National Archives and Records Administration Though the War Department report acknowledged — as is still the case — that experts may disagree over whether the telegram actually pushed the U.S. toward anything that wouldn’t have happened for other reasons, this telegram is generally [seen](http://time.com/vault/issue/1968-02-16/page/106/) as a key step in the United States’ move toward deciding to join in on World War I. After all, at the month’s end, the Associated Press alerted the nation to the fact of the telegram, explaining that President Wilson had already been in possession of the document as German officials protested that they wanted to maintain friendly relations between the two nations. After that, it would be hard to argue that the U.S. could maintain neutrality in the conflict that had already been tearing Europe apart for years. 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