The Codebreakers: The True Story of the Secret Intelligence Team That Changed the Course of the First World War (27 page)

Despite Carranza’s promise to let Pershing’s forces use the Mexican Northwestern Railway, the Mexican army blocked the free flow of troops and supplies. They also repeatedly cut the US army’s telegraph wires. Given the hostility of the environment both natural and political, Pershing put a premium on intelligence, and it was here that the US army finally joined the intelligence war.

Pershing organised his own field intelligence network, and started an information department, whose agents – Mexican, Japanese, and 20 Apache scouts – worked to track Villa and infiltrate his organisation of
bandidos
, who would routinely divest themselves of their guns and blend in with the local population, sometimes even watching movies with unwitting American officers in the cinemas.

Pershing also used ‘radio tractors’, trucks equipped with radio sets, to listen in on Mexican communication. Both the government and Villa’s forces transmitted by wireless, and American intercepts of coded Mexican messages would be sent to Captain Parker Hitt, who wrote the US army’s first book on cryptology; his
Manual for the Solution of Military Ciphers
was published in 1916 at Fort Leavenworth. Hitt used the Mexican Army Cipher Disk to decode the messages, a method involving four numerical alphabets placed on a revolving disc. ‘By tapping the various telegraph and telephone wires and picking up wireless messages,’ Pershing wrote in his report of the mission, ‘we were able to get practically all the information passing between various leaders in Mexico.’

It wasn’t enough, and the campaign was all over by February 1917. The last American cavalry mission had failed to capture its prize, but it had learned much about conducting a new kind of war on foreign soil. The intelligence that Pershing had employed would become critical in his next campaign, in Europe. The Yanks – to the great relief of the Allies – were about to head ‘over there’.

One of the great ‘what ifs?’ of history lies in the German plan to deliver the Zimmermann telegram not via cable, tapped into and intercepted by the British, but by submarine. On her second trip across the Atlantic to a US port (the first, in 1916, had been to Baltimore), the German cargo submarine
Deutschland
docked at New London, Connecticut, on 2 November 1916, bringing 750 tons of dye stuffs, chemicals, and medications against polio, along with Germany’s 0075 code book in a sealed diplomatic pouch that was delivered to the German embassy in Washington. It was this code book that would allow Count von Bernstorff and his staff to decrypt the Zimmermann telegram.

The
Deutschland
was scheduled to sail again for America on 15 January 1917, carrying Zimmermann’s extraordinary offer to Mexico. When Germany resumed unrestricted submarine warfare in February, the
Deutschland
was drafted back into service, and her third mission to America was aborted. Had it not been, it is tantalising to speculate that the course of the entire world war – and the one to follow it – might have been changed. But it was via cable that Zimmermann’s telegram came, and while it filled Room 40 with robust hope, this particular communication had to be handled very carefully.

The U-boat
Deustchland
arriving in Baltimore harbour, July 1916

The problem facing the British was twofold: they had to counter the possibility that the Americans would think the telegram a hoax; and they needed to conceal the fact that the British were reading German dispatches to Washington via the US telegraph cable, and so reading American dispatches as well. They needed to present the telegram to the Americans by disguising its source.

All transatlantic cables passed by the east coast of Ireland or the west coast of England, and were relayed to the central telegraph exchange and copied by the censorship office. Germany sent its telegrams to America by two routes, the first of them evidence of the United States’ native generosity and total naiveté when it came to sophisticated acts of war. At the end of 1916, Colonel Edward House, Wilson’s counsellor and confidant and White House power-broker, had arranged to let the Germans send their telegrams directly to him, via the American cable, in the interest of brokering peace with von Bernstorff in Washington.

The second route was known as the Swedish Roundabout, a method devised in 1915 when Britain complained to neutral Sweden that while, yes, it was reading Sweden’s telegrams, the Swedes were violating the laws of war by sending German messages through their cables to Washington. The Swedes admitted guilt, and then just redirected Germany’s messages to Buenos Aires, handing them over there to the Germans for transmission to Washington. This time, Room 40 did not complain. They just kept reading.

Blinker Hall knew that with no small irony, the answer to his problem lay in Mexico. Zimmermann had sent his telegram to von Bernstorff via both Washington and the Swedish Roundabout. It was von Bernstorff’s duty to transmit the note to Heinrich von Eckardt, Germany’s minister in Mexico. If Hall could somehow get his hands on the copy of the telegram in Mexico, the version sent from von Bernstorff to Mexico would have a different time stamp and serial number than the one intercepted by Room 40, and so it would appear to the Americans – and to the Germans – as if whoever had discovered the telegram had only done so in Mexico and so Room 40’s hands would be ‘clean’. And best of all, the German embassy in Mexico didn’t use the 0075 code. Von Bernstorff would have to recode the message in a code that Room 40 knew well. This would allow them to solve the telegram with certainty.

It was a brilliant idea, but how to pull it off? There is a wonderful romantic story about British agent Thomas Hohler securing the freedom of a British printer facing imminent execution by the Mexicans under suspicion (wrongly) of forging banknotes. In gratitude, the printer had his brother steal the telegram from the Mexican telegraph office, where,
mirabile dictu
, he just happened to work.

In all likelihood, it was good old-fashioned graft or threat of blackmail that got the telegram into Hohler’s hands, and then into those of Room 40, who finished decoding it. Now all that remained was to convince the Americans that this telegram meant war. So Blinker Hall summoned Edward Bell to see him.

Hall liked and trusted Eddie Bell, the Second Secretary of the US embassy in London. He had used him as unofficial liaison for intelligence matters that he wanted to bring to the attention of American ambassador Walter Hines Page. Page, who had been editor of the
Atlantic Monthly
, as well as a partner at Doubleday, Page & Company, publishers, was a devout Anglophile who believed that Britain was fighting for democracy. Hall exploited this by giving Bell details of his interrogation of Franz von Rintelen, as well as von Rintelen’s papers, and those confiscated from the courier James Archibald, which included a plan from the Austrian ambassador to the US, Constantin Dumba, to disrupt the American steel and munitions industries with strikes.

On 19 February 1917, a grey Monday in London, warmer than it had been after an unusually cold winter, Ambassador Page despaired of America and her pacifist president. ‘I am now ready to record my conviction that we shall not get into the war,’ he confessed to his diary. ‘[Wilson] is constitutionally unable to come to the point of action.’

Over at the Admiralty, Blinker Hall hoped that he was holding the smoking gun that would shake Wilson out of his peace dream into the reality of the war he and his team were so arduously fighting. Bell’s initial reaction was one of incredulity when he saw the decrypted note from Zimmermann promising Mexico large chunks of the American south-west should it wage war on the USA. ‘Why not Illinois and New York while they were about it?’ he thundered. But then he calmed, and wondered if this document might be a forgery or a hoax.

Hall knew that he had to proceed with caution, as Bell’s reaction was a barometer to those who would doubtless follow. He explained that British agents had discovered the telegram in Mexico, and after bringing Ambassador Page into the conversation, the trio concluded, at Page’s insistence, that the message would carry maximum weight in Washington if the British government formally presented him with the decrypted telegram. Page was well aware that the British blacklisting of American companies who were accused of doing business with the enemy, as well as the interception of US mail on the North Atlantic and the rough justice meted out to Irish rebels, had made the need to join the Allied cause less clear-cut to many of his countrymen than it was to him.

On Friday 23 February, the patrician and sanguine Foreign Secretary Arthur Balfour was in a state of excitement as he received Ambassador Page at the Foreign Office. He would later say that the moment when he handed over the document that would change the face of the war was ‘the most dramatic of my life’.

Page stayed up until 3 a.m. drafting a careful cover letter to Woodrow Wilson to send with the decrypted telegram, which he transmitted later that day. In his letter, the masterwork of Hall is again evident, for though Room 40 had been in possession of the telegram for more than a month, Hall had clearly told Page otherwise, resulting in the ambassador informing his president that the British had ‘lost no time in communicating it to me to transmit to you … in view of the threatened invasion of our territory’.

Though Zimmermann’s telegram threatened a Mexican invasion of the US only if the US joined the Allied cause, the point was moot when Secretary of State Robert Lansing added insult to injury by revealing to Woodrow Wilson that the Germans had sent their message of war via the American cable that the US had so generously allowed them to use in the name of peacemaking. ‘The President two or three times exclaimed “Good Lord!” … and showed much resentment at the German government for having imposed upon our kindness in this way and for having made us the innocent agents to advance a conspiracy against this country.’

Despite his naiveté about the dark arts of intelligence, Wilson also wondered if the document might be a fake. State Department counsel Frank Polk had already thought of that, and managed to arm-twist Western Union to release the copy of von Bernstorff’s transmission to the German mission in Mexico City.

On 1 March, newspapers in the United States and around the world trumpeted the treachery: ‘
GERMANY SEEKS ALLIANCE AGAINST US; ASKS JAPAN AND MEXICO TO JOIN HER; FULL TEXT OF HER PROPOSAL MADE PUBLIC; WASHINGTON EXPOSES PLOT
’ shouted the
New York Times
’ front page. The White House had leaked the Zimmermann telegram to the Associated Press, and while the
New York Times
felt compelled to say – again with abounding irony – that it hadn’t authenticated the contents, it had no hesitation in revealing the depth of Germany perfidy. It seemed to outraged Americans that it was their own government who had broken open the ugly truth of the German betrayal, which was exactly how Blinker Hall wanted it to appear.

German-Americans immediately saw the whole affair as a provocative fiction. The
New Yorker Staats-Zeitung
editorialised: ‘The passions of the American public that still doesn’t want to hear of war must be aroused so that it may attain that condition forced by similar means on the people of Italy, Great Britain, and Rumania.’

The
Fatherland
’s proprietor and inveterate anti-Allied provocateur George Sylvester Viereck was more bluntly incredulous, calling the telegram ‘obviously faked’ for the simple reason that ‘it is impossible to believe that the German Foreign Secretary would place his name under such a preposterous document’.

On 3 March, Zimmermann put any doubt to rest, astonishingly confessing to plotting the creation of a Japanese—Mexican invasion of the USA. ‘When I thought of this alliance with Mexico and Japan I allowed myself to be guided by the consideration that our brave troops already have to fight against a superior force of enemies, and my duty is, as far as possible, to keep further enemies away from them,’ he declared in a speech. ‘That Mexico and Japan suited that purpose even Herr Haase [Hugo Haase, a German socialist politician and pacifist] will not deny. Thus, I considered it a patriotic duty to release those instructions, and I hold to the standpoint that I acted rightly.’

Even with Zimmermann’s admission, the United States – well aware that it was on the march to war – wanted to silence the doubters that still remained. So in one of the most baroque – and, were it not for the outcome, comic – reversals in the history of codebreaking, the US State Department cabled Ambassador Page to ask if the British would permit someone from the US embassy ‘to personally decode the original message which we secured from the [Western Union] telegraph office in Washington … and make it possible for the department to state that it had secured the Zimmermann note from our own people’.

Blinker Hall was only too happy to go along with the ruse: there was no one in the US embassy who had the slightest idea how to decode the Zimmermann telegram. But in the spirit of the elaborate theatre needed to convince the American people that this was not a slick foreign plot, Eddie Bell came to the Admiralty and looked on as Nigel de Grey decrypted the telegram for him, having no choice but to believe that the jumble of numbers on the telegram meant what de Grey said they did. Ambassador Walter Page accepted at face value Blinker Hall’s claim that it would be pointless to burden the US with the German code book because it ‘would be of no use to us as it was never used straight but with a great number of variations which are known to one or two experts here. They cannot be spared.’