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

by James Wyllie

  The partially decoded telegram had revealed enough for de Grey to realise that the plan detailed within it would send America into bellicose fury. And even though it came from Germany, the plan to keep America out of the war in Europe involved the country that made the USA most nervous, the country right on its own border: Mexico.

  Arthur Zimmermann knew about American paranoia toward Mexico, too. When he was appointed Germany’s Secretary of Foreign Affairs on 24 November 1916, the 52-year-old diplomat became the first non-aristocrat to hold that exalted post, getting there through his wits and cunning. Yet the amiable, forthright Zimmermann, with his bushy reddish-blonde moustache and his duelling scar, was hardly a peasant with a pitchfork who suddenly found himself as Germany’s steward of foreign affairs. Like the Junkers class who governed Germany, he too was from Prussia. After earning a doctorate in law and practising briefly, he joined Germany’s foreign service in 1893, when he was 29 years old. He was consul in China during the Boxer Rebellion, and wound up back in Berlin as Under Secretary of State in 1911. In 1914, as acting foreign secretary, he agreed with Kaiser Wilhelm and Chancellor Bethmann-Hollweg that Germany must ally with Austro-Hungary after the assassination of the Archduke Franz Ferdinand, and drafted the telegram announcing that intention. In 1916, he worked with Roger Casement to foment revolution in Ireland.

  German Foreign Secretary Arthur Zimmermann

  When his predecessor as foreign secretary refused to support a renewal of unrestricted submarine warfare, which had been suspended in late 1915, Zimmermann, a whole-hearted supporter of Germany’s military leaders, got his job. On 31 January 1917, US Ambassador James Gerard was summoned to his office to be officially informed of Germany’s decision. Zimmermann told Gerard that this strategy ‘was a necessity for Germany, and that Germany could not hold out a year on the question of food. He further said, ‘Give us only two months of this kind of warfare and we shall end the war and make peace within three months.’

  Germany’s food situation was central to the desperate military decisions the country made during the winter of 1917–18. Shortly after the Germans resumed their U-boat free-for-all on the Atlantic, and the US responded by breaking off diplomatic relations, a member of the Prussian Diet rose in alarm to report to the assembly that ‘the mortality among elderly people is increasing at a terrible rate’. He also declared that epidemics were spreading among the weakened population, that suicides were increasing and that ‘parents are killing their children rather than see them suffer the pangs of unsatisfied hunger’. If the war lasted another year, Germany itself would die of famine.

  Zimmermann’s incendiary telegram was then, in terms of war strategy, potentially brilliant – after all, the Germans had been using the US as their far western front since the beginning of the war. Rather than being a direct attack, Zimmermann’s note was to be delivered to the Mexican president only if the United States entered the war due to Germany’s unleashing of the U-boats on all Atlantic shipping. It called for an alliance between Mexico and Japan, heavily subsidised by Germany, to wage war on the USA, with the victory prize to be territories the United States had won from Mexico. Zimmermann could not have picked a country more likely to bring the US into the war.

  Mexico had always been a problem for the United States, and vice versa, with territorial wars, skirmishes and horse trading resulting in the USA winning Texas as a state in 1845, and New Mexico and Arizona in 1912. Two years later, President Woodrow Wilson had sent American sailors and marines into Veracruz on a six-month campaign to prevent the German government from sending arms to the Mexican president, Victoriano Huerta, with the resulting violence killing 19 Americans and 129 Mexicans.

  In 1915, Mexican raids had killed 21 Americans as part of the ‘San Diego Plan’, a manifesto drawn up in the small Texas town of San Diego by President Venustiano Carranza to create an extraordinary liberation army of Mexicans, African-Americans, aboriginals and Japanese. Under the red and white banner of ‘Equality and Independence’, this rainbow coalition would slaughter every Anglo male over the age of 16 in their quest to reclaim Texas, Arizona, Colorado, New Mexico and California to create an independent republic. The raids – and the revenge plan – would be called off once the US government recognised Carranza as the legitimate president of Mexico, which it did in the summer of 1915. And that got General Francisco ‘Pancho’ Villa angry.

  Francisco Villa had been born José Doroteo Arango Arámbula, the son of poor peasants in the state of Durango. After his father died, Villa became a sharecropper, then abandoned that for the riches of banditry. He soon became part of a ‘super group’ of bandidos, and ironically, avoided execution upon capture because of the intervention of a powerful landlord to whom Villa had sold stolen goods.

  His punishment was to serve in the federal army, but in 1903, he killed an officer and headed to the state of Chihuahua using the name of his paternal grandfather. The man ‘Francisco Villa’ had been born, and for the better part of the next decade would re-invent himself as a kind of Mexican ‘Robin Hood’, leading his bandidos on raids against the bad hacienda owners in the name of the oppressed people.

  When the Mexican Revolution began in 1910, Villa was in the thick of it, fighting the dictator Porfirio Diaz with the pro-democracy forces, and winding up alongside General Huerta. Huerta, however, was jealous of Villa, and after accusing him of horse theft, insubordination and outright insurrection, Villa found himself standing in front of a firing squad. He was reprieved just in time – so the romantic story goes – by a telegram from Madero commuting Villa’s sentence to prison, from which Villa escaped in time to join the loathed Carranza in a war against the even more despised Huerta – now dictator of Mexico after the murder of Madero.

  Villa fought with Carranza to depose Huerta, along the way getting himself elected governor of the state of Chihuahua in 1913. As governor, Villa printed his own currency, and such was his stature that it was accepted at par at banks in Texas. Villa ordered his paper money also to be taken at par with Mexico’s gold pesos, and in a move that would further cement his ‘Robin Hood of Mexico’ reputation, forced wealthy landowners to give loans – and land – so he could pay and feed his troops, and compensate their widows and children. He also took gold from banks, and true to his bandit origins, took wealthy hostages if the banks were less than forthcoming about where they kept the gold.

  The gregarious, lavishly moustachioed Villa, a teetotaller who had honed his peasant intelligence by learning to read and write in prison, was as quick to laugh as to pull the trigger – once shooting dead one of his soldiers for being drunk and loud while Villa was giving a journalist an interview. Indeed, his larger-than-life persona attracted a Hollywood film crew who followed him around to document his exploits – though Hollywood wasn’t there to witness Villa’s atrocities that finally provoked the USA into action. On 11 January 1916, Pancho Villa’s men hauled 17 American mining engineers from a train in San Ysabel, lined them up and shot them (one man faked death and escaped), prompting the US to put El Paso, Texas, under martial law to prevent its enraged citizens from crossing the border to take revenge.

  Two months later, while darkness still cloaked the dusty border town of Columbus, New Mexico, Pancho Villa launched a raid with 450 of his mounted soldiers, known as ‘Villistas’. For more than an hour the Villistas, hollering ‘Viva Villa! Muerta a los gringos!’, wreaked deadly havoc, setting fire to homes and businesses in the town of 700, and shooting people where they found them. Eighteen Americans and 80 Villistas would die in the attack, with four captured Villistas later hanged.

  President Woodrow Wilson – who had successfully managed to avoid committing the US to a disastrous war in Europe – now did the very thing the Germans had always hoped he would do: get sucked in to Mexico and expend America’s military energies there. Wilson knew he had to take military action, especially in an election year, with high-profile people such as former president and pro-war agitator Teddy Roosevelt mocking his benig
hted pacifism in person and in print. Wilson’s response to Villa’s latest outrage would send American troops deep into Mexican territory under the command of the man who would eventually lead the US army in France. And it would give Germany one last desperate idea to keep America out of the war once and for all.

  With the war in Europe generating death on an industrial scale but no clear victor, and given the enthusiasm of Germany for using the USA as a ‘third front’, it was no surprise that Villa’s attacks on the US were helped by German money. At least $340,000 of German money was funnelled by German agent Felix A. Sommerfeld from a bank account in St Louis to fund arms for Villa.

  The war against Pancho Villa launched by the US in April 1916, known as the ‘Punitive Expedition’, sent more than 14,000 American troops 450 miles deep into Mexico in pursuit of a man who had recently been their trusted ally and receiver of US armaments. Indeed, his military tactics had been so admired by the US that not only did the army study them, but Villa had, in happier days, been invited to the army command centre at Fort Bliss, in El Paso, to meet John J. Pershing, the man who, unbeknownst to them both, would soon be hunting him down.

  Pershing, tasked with the mission to disrupt and end Villa’s campaign, and either capture or, better still, kill him, was a 55-year-old career soldier with an iron jaw, ramrod posture and sharp, unsentimental eyes. He was nicknamed ‘Black Jack’ while teaching at West Point, due to his service with African-American Buffalo Soldiers first in the Indian Wars, and then again in the Spanish-American War – a nickname that had been softened from something far more offensive. Pershing’s mission in Mexico was highly sensitive. The USA had the tacit support of Mexican president Venustiano Carranza, but if Pershing’s forces pushed too hard, a total war could easily result, and the US wanted to punish Villa, not ignite the bone-dry tinder that was Mexico.

  General John Pershing in France

  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 br
ing 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.