Zimmerman Telegram
Running on the slogan, “He kept us out of war,” voters elected Woodrow Wilson to a second term in November 1916. In January of 1917 British cryptographers decoded a telegram sent by Germany’s Foreign Minister, Zimmerman, to the German Minister to Mexico. Zimmerman authorized the minister to offer to Mexico the territory taken by the U.S. during the Mexican-American War if Mexico entered World War I on Germany’s side. While seemingly far-fetched today, at the time Mexican-American relations were troubled ever since the Mexican Revolution in 1911. Concerned about German influence in Mexico, President Wilson ordered U.S. forces to Veracruz for six months in 1914. In March of 1916 supporters of Mexican General Pancho Villa, an aspirant for power in Mexico, raided New Mexico. U.S. General Pershing failed in his campaign to capture General Villa.
Zimmerman also advised the minister that Germany planned to break the Sussex Pledge and resume unrestricted submarine warfare. The German government realized the telegram likely would antagonize President Wilson. The government though believed Germany would win the war before the U.S. was able to mobilize enough to become a factor in the war. In an effort to avoid revealing that the German encryption was cracked, Britain waited until February 24 of 1917 to reveal the telegram’s contents to President Wilson. The press reported the details of the telegram on March 1.
Note: Ironically, because Britain had severed Germany’s underwater telegraph cables, as a neutral nation the U.S. often forwarded messages from Germany to the German embassy in Washington DC. Britain was able to intercept the Zimmerman telegram because it spied on the U.S. and its diplomatic traffic. Thus, the U.S. helped Germany deliver the Zimmerman telegram to Mexico and President Wilson learned about the telegram because Britain spied on the U.S.