Hall had no doubt as to the telegram’s importance. “This may be a very big thing,” he told de Grey, “possibly the biggest thing of the war. For the present not a soul outside this room is to be told anything at all.” And that included even Hall’s superiors in the Admiralty.
Hall hoped he could avoid revealing the telegram altogether. There was a chance that Germany’s declaration of unrestricted U-boat warfare by itself would persuade President Wilson that the time for war had come. Hall’s hopes soared on February 3, 1917, when Wilson broke off diplomatic relations with Germany and ordered Ambassador Bernstorff to leave. But Wilson stopped short of calling for war. In a speech that day, Wilson stated that he could not believe Germany really intended to attack every ship that entered the war zone and added, “Only actual overt acts on their part can make me believe it even now.”
Hall realized the time for action had come—that he had to get the telegram into American hands but at the same time protect the secret of Room 40. Through a bit of skulduggery, Hall managed to acquire a copy of the telegram as it had been received in Mexico, from an employee of the Mexican telegraph office, thereby allowing Britain to claim that it had obtained the telegram using conventional espionage techniques. On February 24, 1917, Britain’s foreign secretary formally presented a fully translated copy of the telegram to U.S. ambassador Page.
WILSON WANTED to release the text immediately, but Secretary Lansing counseled against it, urging that they first confirm beyond doubt that the message was real. Wilson agreed to wait.
That same day, the news broke that a Cunard passenger liner, the Laconia, had been sunk off the coast of Ireland, after being struck by two torpedoes. Among the dead were a mother and daughter from Chicago. Edith Galt Wilson had known them both.
WILSON AND LANSING resolved to leak the telegram to the Associated Press, and on the morning of March 1, 1917, America’s newspapers made it front-page news. Skeptics immediately proclaimed the telegram to be a forgery concocted by the British, just as Lansing and Captain Hall had feared would happen. Lansing expected Zimmermann to deny the message, thereby forcing the United States either to disclose the source or to stand mute and insist that the nation trust the president.
But Zimmermann surprised him. On Friday, March 2, during a press conference, Zimmermann himself confirmed that he had sent the telegram. “By admitting the truth,” Lansing wrote, “he blundered in a most astounding manner for a man engaged in international intrigue. Of course the message itself was a stupid piece of business, but admitting it was far worse.”
THE REVELATION that Germany hoped to enlist Mexico in an alliance, with the promise of U.S. territory as a reward, was galvanizing by itself, but it was followed on Sunday, March 18, by news that German submarines had sunk three more American ships, without warning. (To add to the sense of global cataclysm, a popular rebellion sweeping Russia—the so-called February Revolution—had caused the abdication on March 15 of Tsar Nicholas and filled the next day’s papers with news of violence in the streets of Russia’s then capital, Petrograd.) A tectonic shift occurred in the nation’s mood. The press now called for war. As historian Barbara Tuchman put it: “All these papers had been ardently neutral until Zimmermann shot an arrow in the air and brought down neutrality like a dead duck.”
Secretary Lansing was elated. “The American people are at last ready to make war on Germany, thank God,” he wrote in a personal memorandum, in which he revealed a certain bloodlust. “It may take two or three years,” Lansing wrote. “It may even take five years. It may cost a million Americans; it may cost five million. However long it may take, however many men it costs we must go through with it. I hope and believe that the President will see it in this light.”
Wilson gathered his cabinet on March 20, 1917, and asked each member to state his views. One by one each weighed in. All said the time for war had come; most agreed that in effect a state of war already existed between America and Germany. “I must have spoken with vehemence,” Lansing wrote, “because the President asked me to lower my voice so that no one in the corridor could hear.”
Once all had spoken, Wilson thanked them but gave no hint as to what course he would take.