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The Fountain | Autumn 2014 | Issue 19
Spying on Your Friends: Breaking American Codes in the First World War Recent revelations that the American National Security Agency (NSA), assisted by the British Government Communications Headquarters (GCHQ), have targeted Germany and other friendly countries – including, most memorably, the NSA’s intercepting Angela Merkel’s telephone calls – have caused widespread public interest and, in some quarters, consternation. Yet throughout modern history, countries have sought to intercept the communications not only of their adversaries but also of their friends. The most famous codebreaking organization in British history is that of GCHQ’s predecessor at Bletchley Park, whose breaking of German codes in the Second World War helped shorten the conflict and saved countless lives. But GCHQ’s history stretches back to the founding in 1914 of two codebreaking organizations: a naval group named Room 40, and a lesser known army organization called MI1(b). The British were a bit late to the game. Other countries – France, Russia, AustriaHungary, among others – already possessed longstanding diplomatic codebreaking units. Room 40 focused initially on breaking German naval codes, but eventually it expanded its efforts mainly to enemy diplomatic codes. Most famously, it successfully deciphered the Zimmermann Telegram a couple of months before the United States entered the war on the Allied side in early 1917. Germany had offered three U.S. states to Mexico in exchange for an alliance, and the exposure of the plot to a grateful American government caused a sensation in the American press. Whereas Room 40 concentrated largely on enemy codes, MI1(b) took on those of allied and neutral countries, including the United States. Initially,
By Daniel Larsen (e2013)
MI1(b) began the war working to break German army radio codes. In 1915, as the Western front bogged down to a stalemate, the German military rapidly replaced its radio communications with telegraph lines, which the British could not intercept. The codebreaking group suddenly found itself with little to do. They turned to trying to break neutral diplomatic codes, beginning with those of the United States. The Americans did little to make it difficult for them: the U.S. Department of State used the same codebook, unchanged, from 1910 to 1918. They made it even easier by arranging the codebook alphabetically. It took the inexperienced group some time, but by the end of 1915, MI1(b) succeeded in reconstructing it. The British then had unlimited access to virtually all American diplomatic telegrams that crossed the Atlantic. One might imagine that breaking these codes gave the British a significant advantage over their neutral American cousins – even, perhaps, the ability to help manipulate them into joining the war. In reality, at least between 1915 and 1917, the British probably would have been better off if MI1(b) had left the State Department’s codes entirely alone. The British government under Prime Minister H. H. Asquith was bitterly divided about the role of the United States in the Allied war effort. One faction saw the Americans largely as impotent and unwelcome interlopers. Their efforts at mediating a compromise peace were regarded as dangerous, their objections to aspects of the British blockade as damaging a vital tool in winning the war. The meddling Americans, they believed, mostly deserved only a brusque rebuff. But another faction had come to doubt whether the British could win the war without American support. They viewed
the Americans’ peace efforts as a potential way of extricating them from an unwinnable war, and they recognized and feared the United States’ considerable economic and financial power. As the British dug themselves deep into debt, American loans became paramount for the continuation of the war. The Allies, they believed, had to do what they could to keep the Americans content; otherwise, the war would go from quagmire to disaster. And so these diplomatic decrypts provided the British with ammunition for their own infighting, rather than helping improve their policy towards the United States. MI1(b) gave the War Office and, often, the Admiralty the ability to keep a close watch not only on the American Embassy but also on the Foreign Office. If telegraphed to Washington, every conversation between the Foreign Office and the American Embassy was immediately subject to military scrutiny. Also, because the still-neutral Americans maintained relations with Germany,