To this end, they sent coded information about her to their agents in France, referring to her as agent H21, knowing that the code had already been broken by the French. The coded messages were, indeed, intercepted and read by French intelligence officers, sowing the seeds of doubt about Mata Hari in their minds. Was she a double agent working for France and Germany? Or had she simply turned and become a German agent?
Mata Hari returned to Paris to meet with Captain Georges Ladoux, chief of French military intelligence, and on February 13, 1917, Mata Hari was arrested and jailed in Saint Lazare prison, where her treatment was deplorable. She was forced to live in filthy conditions, isolated from other prisoners. She was not permitted to bathe, nor was she provided with a change of clothes. Prison officials allowed her fifteen minutes of physical exercise each day. Despite such horrible circumstances, Mata Hari maintained her innocence during her interrogation sessions, at one point writing a note to the investigator of her case, Pierre Bouchardon, that read, “You have made me suffer too much. I am completely mad. I beg you to put an end to this.”
At her trial, it was no surprise to anyone when she was unanimously condemned to death. As a final insult, she was first required to pay court costs. The firing squad assembled in the predawn hours of October 15, 1917.
In the final minutes of her life, Mata Hari faced the thirteen soldiers in the firing squad, her head held high. She refused the customary blindfold. Part of her legend includes the notion that she blew a kiss to the soldiers before shots cracked the morning stillness. Although it was clearly unnecessary, the officer drew his revolver and delivered the traditional coup de grâce, a single shot into the spy’s ear. With no one to claim the body, her remains were delivered to a medical school, for dissection by students.
Was Mata Hari a spy? Yes, but a far cry from being the “greatest woman spy” in history. It’s debatable if she was, in fact, a double agent. Some historians believe she spent fifteen weeks in a “spy academy,” learning the skills of the trade, including using various methods of coded communication, memorizing photographs and maps, and becoming familiar with weapons. Such training would have also included warnings about “fool spies,” or double agents. Mata Hari consistently told her interrogators that she never attended any such spy training sessions. Several biographers agree.
Even long after the war, the “little mysteries of counterespionage” prevented all the facts of Mata Hari’s case from being released. In fact, when Pierre Bouchardon published his memoir in 1953, he claimed that “professional secrecy” prevented him from saying more about the evidence that convinced him that Mata Hari was a spy who had to face a firing squad.
While U.S. intelligence agencies were not prepared to keep track of and stop German operatives who had slipped into this country, their counterparts in England did have the personnel and system to take on the German espionage machine. True, the British had more at stake in the war, but they also were much better prepared to fight Germany in espionage battles, with some of their best work done in the area of codes and ciphers.
Cable messages from Europe to the United States traveled through transatlantic cables that passed deep in the English Channel. The British saw the cables as an opportunity to gain access to secret diplomatic messages sent from Berlin to its ambassador in Washington, D.C. Knowing they couldn’t tap the cables the way they could tap phone lines, the British did the next best thing. The cable ship Telconia cut all five of the cables that carried communications through the channel. To make sure that the sabotage had a lasting effect, the Telconia rolled up a few of the cable ends on her drums and carried them to England. This act of sabotage was Great Britain’s first offensive act of the war.
As a result of the cut cables, Germany lost its most secure long-distance communications system. The Germans now had to rely on radio transmissions from their powerful wireless station at Nauen, a few miles from Berlin. Which was exactly what the British military knew they would have to do. And once the Germans began sending wireless messages, MI8, the British code breakers, began plucking them from the air. Of course, all German correspondence was sent in a complicated cipher system, so that was when the hard work began for the code breakers of MI8.
The intercepted messages were usually no more than rows of numbers in four- and five-digit groups, with an occasional three-number group included. For example, 67893 was the code word for Mexico. Such messages, sometimes as many as two hundred a day, were snagged day and night by the operators in Room 40, MI8’s cryptography center. To make the messages more difficult to decipher, the Germans frequently added another layer of security to their text by enciphering a message that was already written in code! In other words, the British code breakers needed to solve the cipher message before they could even take a crack at the coded message.
Given how this double disguising of a secret message could make decoding so much more difficult, it remains a mystery why the German telegram that finally convinced the American president to join the Allies on the battlefield in 1917 was simply a coded message.
While the task that faced the cryptanalysts in Room 40 was very intellectually demanding and physically taxing, the Germans committed some blunders in the way they sent their secret radio messages, giving the British help in their task. The first mistake of German intelligence was the error of arrogance, believing that the British were not up to the challenge of deciphering their messages. Another mistake they made was sending duplicates and even triplicates of some of their messages, with each one using a different cipher key. This ill-advised practice meant that the code breakers had a couple of different versions of the same message, giving them a much better chance of cracking the cipher. The men of Room 40 were, in the words of one historian, “reading Berlin’s messages more quickly and correctly than the German recipients.” This group of cryptography amateurs, who were generally recruited from college faculties, was able to achieve its success with “ingenuity, endless patience, and sparks of inspired guessing.”
On several occasions Room 40 received an unexpected but welcome gift when a German codebook was recovered after a sea battle and presented to the British code breakers. One such gift was a codebook from the German ship Magdeburg, a light cruiser that ran aground on an island off of Finland. When Russian ships quickly bore down on the cruiser, the captain of the stranded ship immediately did what all naval officers were taught to do: he ordered his signalman to bring him the ship’s codebook so he could throw the book, wrapped in lead covers, into the sea. But before the signalman could deliver the book to his captain, he was killed by Russian guns. When the Russians recovered his body, the sailor was still clutching the codebook in his arms.
The Russian admiralty decided that their British allies could make better use of the codebook than they could, so it was sent to London. The codebook was a bonanza for the British code breakers. Not only did it contain the columns of code “words”— groups of randomly selected numbers — on which the messages were based, but it also included a changeable key to the cipher systems used to obscure the coded messages.
The director of Room 40, Admiral Sir William Reginald Hall, was constantly on the lookout for any German codebook he could get his hands on. In December an iron-encased sea chest was delivered to his office. The chest had been hauled to the surface in the net of a British fishing trawler. It turned out that the chest was from a German destroyer that had been cornered and sunk by British warships. Among the personal papers and nautical charts in the chest, Hall discovered a codebook. It took the code breakers of Room 40 a few months to discover that the book contained the code system used by the German military to communicate with their naval attachés abroad.
After hours of hard work and their “inspired guessing,” the code breakers scored many triumphs. Their greatest success, however, came in 1917, when the war was at a critical point.
For nearly three years the war had taken its toll on the fighting nations. England maintained hope that, despite President Woo
drow Wilson’s continued belief in his brand of neutrality, the Americans would reconsider, join the fight, and tip the balance of war in favor of the Allies.
On January 16, 1917, in a clear attempt to convince the Mexican government to help Germany in the war, Arthur Zimmermann, the German foreign secretary, sent a telegram to Count von Bernstorff, the German ambassador in Washington. The foreign secretary wanted to be certain that this message reached von Bernstorff, so he made arrangements for it to be carried aboard a U-boat to Sweden and from there to Washington through diplomatic channels.
As luck would have it, the departure of the sub was delayed. Impatient, Zimmermann turned to his second option: sending the message to his ambassador through the U.S. State Department. Although Wilson considered the United States to be neutral, he allowed messages to be sent to von Bernstorff via the State Department as a courtesy. The telegram sent, Zimmermann waited for a reply. What Zimmermann didn’t know was that the British were doing a thorough job of intercepting German wireless transmissions.
The first thing about the Zimmermann telegram that two Room 40 code breakers, Reverend William Montgomery and Nigel de Grey, noticed was its length, more than a thousand groups. Although the length itself was not suspicious, it was out of the ordinary. Then de Grey noticed the top group of numbers in the message, 13042, a variation of 13040, indicated a German diplomatic code. Since Room 40 had a copy of the 13040 codebook, they began using it to decipher the message.
As Montgomery and de Grey slowly made their way through the message, they noticed more and more oddities. For example, 97556 appeared near the end of the message; the 90000 family indicated important names that were not used very often in messages. We can imagine their shock when they realized that 97556 stood for Zimmermann. That single name fired the men with excitement as they began working on the message from the beginning.
In time, some of the coded “words” began to give up their secrets. They found most secret and For Your Excellency’s personal information. The men pushed on, discovering Mexico and Japan in the text. What could that mean? And what was Germany’s interest in Mexico? How did Japan figure into the plan? The men could not think of a reason for the connection among Germany, Japan, and Mexico. Quickly thumbing the pages of the codebook, the men worked on at a fever pitch.
They learned that there were two parts to the telegram. The first part — the longer of the two — carried bad news for all ships at sea, but especially American ones. Zimmermann was informing von Bernstorff that the German U-boat fleet would resume “unrestricted” submarine warfare on February 1. From that day onward, all ships, even those from neutral nations, would be fair game for deadly submarines patrolling the dark waters of the Atlantic.
Indeed, on February 3, the American steamship Housatonic was torpedoed without warning. This unprovoked attack on a passenger ship was another in a long line of similar acts of belligerence that had occurred in previous years. The most famous was the sinking of the steamship Lusitania in 1915, which killed all but two dozen of its 1,924 passengers, 114 of whom were Americans. The United States demanded that Germany disavow the attack on the Lusitania and make immediate restitution. Germany refused to do either. In March 1916 the French Sussex was sunk by a German submarine attack in the English Channel. The United States threatened to cut off diplomatic relations with Germany unless such attacks stopped.
If the first part of the telegram was ominous, the second section must have sent shivers of fear through Montgomery and de Grey. Although there were about thirty spots in the message that the men could not figure out, they had learned enough to know that it was time for them to notify their superior of their discovery.
Montgomery quickly fetched Admiral Hall. The head of Room 40, nicknamed “Blinker” for the uncontrollable twitching in his eyes, hurried into the room and stood in front of de Grey’s desk. Without saying a word, de Grey stood and handed the message to the small, ruddy-faced man. Hall’s eyes took in what Montgomery and de Grey had discovered. His eye twitches became more pronounced as he tried to assess the impact of what he was reading.
Hall well understood the gamble the Germans were taking. In two weeks they would unleash the full fury of their two hundred U-boats, in an effort to choke off the stream of American supplies that was keeping the Allied nations in the war. Surely, the U.S. would not permit their ships to be sunk by a belligerent nation. They would retaliate — unless their forces and attention were focused on a hot spot closer to home. Germany wanted Mexico to engage the Americans enough so they would be unable to send troops to help the Allies.
Zimmermann did not spell out what he hoped Mexico could do to assist the German war effort. The Germans weren’t looking for a long-term commitment, confident, as the telegram states, that the submarine warfare would compel “England to make peace within a few months.” With Mexico sharing an extensive border with the United States, perhaps Germany expected Mexico to stage attacks in their “lost territories in Texas, New Mexico, and Arizona.”
Arthur Zimmermann had no idea that “Blinker” Hall had read his secret message. But now that Hall had read it, what could he do with this information? On one hand, he believed that President Wilson, faced with the information in the telegram, would declare war on Germany. On the other hand, to share the telegram with Wilson would surely alert Berlin that the British had been reading their secret messages. As he walked back to his office, Hall considered ways that he could share the intelligence in the Zimmermann telegram and establish its authenticity without letting Berlin know that Room 40 had intercepted and read hundreds of their secret messages.
Hall decided that he needed to find a way to get a copy of the telegram that von Bernstorff would next have sent to Heinrich von Eckardt, the German ambassador in Mexico. He was convinced that there would be small but helpful differences between the original telegram sent by Zimmermann and the version that von Bernstorff would have sent to Mexico City. The message itself would be the same. Hall was sure that von Bernstorff would copy it carefully, but he was equally certain that it would contain telltale differences. For one thing, the dateline at the top of the telegram would be different, as well as the address and the signature. Yes, he needed to get his hands on a copy of that telegram, which would provide Wilson and Congress with proof of Germany’s intent with Mexico without compromising the activities of Room 40. Hall counted on Berlin to blame someone at the embassy or in the Mexico City telegraph office for letting the telegram fall into the hands of the Americans.
But how would Hall get that telegram? That would take some doing, he admitted. Then Hall remembered Mr. H., one of his trusted operatives. It was Mr. H. who had alerted MI8 to the suspicious activities of Sweden’s chargé d’affaires in Mexico City, Folke Cronholm. Sharp-eyed Mr. H. had noticed that Cronholm was making frequent visits to the telegraph office, far more visits than one would expect from a representative of the Swedish government, given the limited relationship between that government and Mexico.
Mr. H.’s report on Cronholm included a mention of the fact that von Eckardt had recommended Cronholm for an official decoration because, as the German ambassador wrote, Cronholm “arranges the conditions for the official telegraphic traffic for your Excellency.” Odd, Hall had thought on reading this, that Berlin would not simply give Cronholm some second-tier medal in a private ceremony. Why such public recognition for the Swedish diplomat?
Hall could think of only one reason for such an honor. And that reason stunned him. Was Cronholm helping to transmit coded German messages overseas? The answer came as soon as Room 40 deciphered some intercepted Swedish cable messages. As expected, each one began with a handful of Swedish code groups. However, the messages continued in German. Room 40 took to calling this ruse the Swedish Roundhouse. With this new information, British intelligence had begun monitoring Swedish cables. And it had all started with the keen observations of Mr. H. Now Hall wondered if Mr. H. could assist him again. He contacted his operative and made his request. Then
he waited for Mr. H. to do his work.
Mr. H. quickly began talking to his contacts in the city. Soon he heard of a British printer in Mexico City who had been falsely arrested for printing counterfeit money. Mr. H. intervened with the British minister, who got the frightened printer released from custody and the charges against him dropped. The printer, overjoyed to be free, told Mr. H. that he would welcome the opportunity to repay the agent for his intervention. As a matter of fact, Mr. H. told him, there was a favor the printer could do for him.
The British agent had learned that the printer’s good friend — in fact, the first person he contacted for advice when the accusation leveled at him sent him into a panic — worked in the Mexican Telegraphic Office. Would he be able, Mr. H. wondered, to get a copy of the original telegram sent by von Bernstorff to von Eckardt? The printer was sure his friend could do that. He was as good as his word. Once Hall received the telegram from his agent, he was ready to approach President Wilson.
British government leaders didn’t present the Zimmermann telegram to Wilson for a few weeks. Hall reminded them that outrage was growing in America over Germany’s announcement late in the day of January 31 that the German navy would resume unrestricted submarine warfare. In fact, that policy provoked the U.S. government to cut diplomatic relations with Germany in February.
On February 24, when Hall sensed that the Zimmermann telegram would tip the balance in favor of the U.S. joining the Allied forces, the British home secretary presented the telegram to President Wilson. One week later, news of the Zimmermann telegram was splashed across the front page of American newspapers. On April 6, 1917, the Congress of the United States declared war on Germany and its allies.
Although the battlefield mayhem continued for another year, the added strength of U.S. troops proved to be too much for Germany. David Kahn, a leading authority of cryptography, wrote this about the Zimmermann telegram: “Never before or since has so much turned upon the solution of a secret message.”
The Dark Game Page 7