The most colossally stupid and historically consequential mismanagement of classified war plans in an electronic transmission belongs to Arthur Zimmermann, the German foreign minister who dispatched an encrypted telegram to Mexico, via Western Union, offering Texas, Arizona, and New Mexico as a war trophy if Mexico would side with Germany in the First World War.
The diplomatic dispatch, dated January 17, 1917, was part of Zimmermann’s foreign-policy strategy, which was as ambitious as it was delusional. Two years earlier, Zimmermann had cautioned James Gerard, the American ambassador in Berlin, about the potential for “a half million trained Germans” living in the United States to mobilize their Irish-immigrant counterparts in a revolution to overthrow the U.S. government. “I thought at first he was joking,” Gerard reported to the State Department, “but he was actually serious.”
Zimmermann considered himself an authority on the Americans based on a train trip he had taken across the U.S. in 1904. Zimmermann felt that the best way to keep the United States out of the war in Europe was to create enough disturbance along the U.S.-Mexico border to distract the Americans from the conflict happening across the Atlantic. To this end, Zimmermann had helped finance Pancho Villa’s infamous cross-border raid on Columbus, New Mexico, in 1916, and he had encouraged William Randolph Hearst to make a silent-movie series—released in January 1917—about Japanese spies who ally themselves with Mexicans in a plot to invade the United States. Episode 10 of the series, which was called Patria, features an all-out Japanese assault on New York City.
In February 1917, Germany had decided to reintroduce unrestricted submarine warfare, following a year-and-a-half hiatus after the sinking of the Lusitania by a German U-boat, which had killed 1,195 innocent civilians, including 123 Americans. Zimmermann feared that the renewed attacks on passenger ships could provoke the United States to side with the Allies. To prepare for this contingency, Zimmermann devised a plan that, as outlined in his telegram, called for the Germans to enlist Mexico and Japan in an invasion of the United States, with the understanding that Germany would allow Mexico to annex the southwestern corner of the country.