ISBN 0-7006-1013-8
292 pages

Acknowledgments; List of Abbreviations; Introduction; maps; photos; Notes; Bibliography; Index

   David Alvarez, by virtue in part to his stint as scholar-in-residence at the National Security Agency, has become one of the leading historians of signals intelligence during the World War II era. His other books on the topic include Nothing Sacred: Nazi Espionage against the Vatican, 1939-1945 and Allied and Axis Signals Intelligence in World War II.
   In his latest work, Alvarez sets out to investigate a less familiar facet of sigint. While there have been many books on the impact of Ultra, Magic, and other cryptanalysis on air, ground, and naval operations, relatively little has been written about the influence of signals intelligence on diplomacy. Here Alvarez looks into what President Franklin Delano Roosevelt and the American State Department learned from such intelligence, and how that knowledge affected their decision-making. Along the way, Alvarez ends up writing a history of US Army signals intelligence during World War II which in many ways complements the naval side of intelligence as chronicled in Tracking the Axis Enemy: The Triumph of Anglo-American Naval Intelligence by Alan Harris Bath.
   Following the dismissal of Herbert Yardley and the closing of his Cipher Bureau in 1929—"Gentlemen do not read each other's mail"—the War Department in 1930 created the Signal Intelligence Service within the Signal Corps under William Friedman. Unlike Yardley's "Black Chamber," however, the SIS was charged not with cracking enemy codes but with simply training individuals in cryptology, evaluating code machines, and testing American codes for weaknesses. Friedman gradually expanded these responsibilities to include studying the simple codes of Prohibition-era rum-runners, Soviet commercial codes, and eventually Japanese ciphers. Because of official indifference and the lack of intercepts, progress in solving foreign codes was very slow.

   As late as 1936, not a single diplomatic message decrypted and translated by SIS had ever gone to the White House. Decrypts were not circulated to the State Department or within the War Department; indeed, no one in the former agency and only a handful in the latter even knew what Friedman's unit was doing. Codebreaking may have provided a rare insight into Japanese foreign policy, but it was an insight granted only to the six men and one woman who then constituted the Signal Intelligence Service. This curious situation reflected the ambivalence with which the army still viewed its radio intelligence service. As noted earlier, the army thought of that service as primarily a code compilation office and a cadre for the training of cryptologists for wartime. It saw little use for peacetime interception and solution of foreign communications, and it wasn't even sure that such activity was legal.

   Despite this lack of enthusiasm on the part of the Army and the Federal government, Friedman and his little team continued to work on Japanese systems. In 1938 the SIS began to attack German codes. Later in the same year Italy and Mexico were added to the target list. By 1939 Friedman was receiving vastly increased volumes of intercepts from monitoring stations and via an agreement with the American company RCA for copies of foreign traffic sent through commercial channels.

   No once can say how much sigint passed across the desks of President Roosevelt and his diplomatic advisers in the last months of peace. Whatever the amount (and it would have been slight), it probably had little impact on policy making. The problems facing American policy makers at the end of the decade were not so much those of intelligence as of resources and influence. American ambassadors in Berlin, Rome, Tokyo, Paris, and other major capitals conscientiously supplied Washington with a stream of generally accurate (and occasionally insightful) dispatches on political affairs. These reports were supplemented by press coverage of the deteriorating international situation. By 1939 Roosevelt did not need decrypts to conclude that Hitler was a serious threat to peace and democratic values, or that a commonality of interest linked the regimes in Berlin, Rome, and Tokyo. The White House and the State Department knew what was happening in Europe and the Far East; they just could not do anything about it as they struggled in vain against timid isolationism and military weakness at home and intractable nationalism and fascism abroad. In short, signals intelligence was at this time largely irrelevant to American policy makers. On the strategic level it told them little that they did not already know; on the tactical level it was too limited to inform particular diplomatic decisions even if the domestic and international environment had not narrowed the range of those decisions.

   Shortly after the German invasion of Poland in 1939, the Army authorized over thirty new positions in the SIS along with a significantly increased budget. However, as Friedman well knew, trained cryptanalysts could not be produced overnight. During the next year the SIS continued its work on codes of the same four nations. Although Mexican systems were thoroughly penetrated, only the lowest grade of Italian codes were broken, and virtually no headway was made against the Germans. The most important successes were made against Japanese codes. In February 1940 a new, uncracked code replaced the old, compromised Japanese diplomatic system. The attack against the new code, known as Purple, was increased when SIS expanded again in January 1941, and for the first time resources were available to attack Japanese military codes as well as the diplomatic ones.
   At the same time, as interest in sigint increased, a considerable turf war arose among the Army, Navy, Coast Guard, FBI, and Federal Communications Commission about dividing responsibility for interception and cryptanalytic work as well as distribution of the resultant intelligence "product." Everyone wanted a piece of the pie. The situation was further complicated by the question of cooperation with the British.
   In September 1940 the SIS made the critical discoveries which solved Purple, and within a few weeks analog machines had been built to expedite the daily solutions of top-level Japanese diplomatic traffic.
   Great strides were made in the ensuing months. The US and UK reached an important agreement for collaborating and sharing sigint even though the US was not yet at war. The Army and Navy agreed to a division of responsibilities which left all diplomatic traffic in the hands of the SIS. Perhaps most importantly, with critical Japanese messages being steadily decrypted and the United States being drawn closer to war, throughout 1941 the State Department and FDR himself finally began to take some interest in the intelligence summaries provided by the SIS thanks to their substantial achievements. Still, Alvarez is careful to place this intelligence cornucopia in context.

   Signals intelligence also became more visible on the horizon of American policy makers as their immediate preoccupations shifted from Europe to the Far East. As the central question changed from "What will Berlin (or Rome) do?" to "What will Tokyo do?" the dependency on Japanese messages became a strength rather than a weakness. The Magic background to Pearl Harbor has been examined and reexamined in hundreds of books and articles, and there is little point in detailing once again the futile negotiations in the summer and fall of 1941 that were the prelude to war in the Pacific. It is easy to exaggerate the importance of signals intelligence in the diplomacy of those months. In the matter of sigint the question is not so much "What did Washington know?" (the answer being "Whatever Tokyo chose to tell its embassies"—information that did not include the intention to attack Pearl Harbor on 7 December 1941), but "What difference did it make?" The answer to the latter question is "Very little." Events in the final months of 1941 would have played out pretty much the same even if Washington had had no access to Japanese diplomatic communications.

   The story having been told many times already, Alvarez does not offer a lengthy account of the intelligence failure at Pearl Harbor, but he picks up the thread with the broken wrecks still smoking at Battleship Row. When the United States was plunged into war, the SIS was suddenly required to undertake more cryptanalytic tasks than ever before while simultaneously finding and training many more specialists. Pearl Harbor also set the stage for a major transformation of the function and responsibilities of the SIS.

   Pearl Harbor convinced Secretary of War Stimson that something had to be done about the army's signal intelligence program. Even before the debacle in Hawaii, the deficiencies of the program were increasingly apparent. SIS decrypted only a small percentage of the total number of diplomatic messages it intercepted each day, and only a small number of the decrypted messages were deemed worthy of translation—indeed, in its selection of targets to monitor and cryptanalytic problems to attack—SIS was left largely to its own devices, receiving from MID little more than general directives to intercept Japanese, German, and Italian communications. Rarely, if ever, before Pearl Harbor did the codebreakers receive guidance from military or diplomatic authorities regarding the types of information desired. Translations were passed, without comment or analysis, to MID, where they were read by a handful of officers, who then selected a small of amount of these translations for circulation, again without commentary or analysis, to the army's Magic distribution list. In the parlance of the intelligence profession, Magic translations were "raw" intelligence, untreated by the application of informed analysis by specialists with access to other sources of information. Those on the distribution list read the translations, made of them what they could, and then returned them to the courier. Prohibited from retaining translations, the readers could not refresh their memory of earlier messages or place that day's messages in a larger context.

   Alvarez charts the growth and evolution of the SIS, emphasizing the social aspects of the move into new quarters, the lack of suitable facilities, security lapses, working conditions, and the adjustment from a small brotherhood of specialists to a large, bureaucratic branch of an Army at war.
   The book continues with details of shifting SIS priorities for targeting specific diplomatic and military traffic, some highlights of SIS successes (such as the harvest of intelligence gleaned from the messages dispatched from Berlin by General Oshima), penetration of Spanish systems, and interestingly, the way Axis cryptanalytic successes aided the SIS.

   Sometime in late 1942 or early 1943, Arlington Hall began to read the messages in JAS, and what the codebreakers saw set off alarms across Washington. The JAS traffic passing along Berlin-Helsinki-Tokyo circuits revealed that, in addition to successes against British, Russian, and Turkish communications, the Axis had cracked several American diplomatic ciphers, including the so-called strip cipher that carried the State Department's secret messages. This news caused consternation at State, but it was seized upon with unseemly glee by Arlington Hall. With scarcely a thought for leakage of American diplomatic secrets, the codebreakers realized that if the Axis were exchanging decrypted American radiograms, they could advance their recovery of JAS key and code by using copies of State Department cables as cribs. In early 1943 Tokyo introduced a second military attache system (JAT) for signals intelligence liaison messages. Initial efforts against this system were retarded by lack of traffic and the pressure to exploit the success against JAS, but by late 1944 the codebreakers were reading their first messages in the new system. The solution of JAS and JAT provided American intelligence a unique opportunity to monitor Axis efforts to penetrate Allied communications. It also allowed the American codebreakers to advance their work against certain targets (e.g., Turkey and the Soviet Union) by learning from the experience of their Axis counterparts. In this case the enemy became unwitting collaborators of American signals intelligence.

   Alvarez also discusses SIS efforts against Latin American countries and the European neutrals. Other targets included the Free French, China, various Allied governments in exile, and—according to some fragmentary records—the British.
   And of course resources were expended on breaking the codes of the USSR. Alvarez devotes a full chapter to an examination of "the Russian problem," beginning with 1917 and including a lengthy account of the Amtorg affair in which various US agencies tried to crack the cipher of the Soviet commercial agency in the US. In the ensuing years little work was done against the Soviets until October 1940 when monitoring stations were directed to intercept Soviet diplomatic traffic. However, no cryptanalysis was attempted until early 1941 and these efforts were soon shelved. "Perhaps the War Department interest in Moscow's communications became less urgent after Hitler attacked the Soviet Union on 22 June 1941 and Russia moved to the side of the angels."

   After the German invasion of the Soviet Union in June 1941, Prime Minister Churchill had directed GCCS to cease sigint operations against the new Russian ally. Although this directive was in the main implemented, Bletchley Park continued to work on Russian weather ciphers largely because Russian weather reports provided a crib for reading the main German weather cipher, which repeated Soviet weather messages intercepted and decrypted by German signals intelligence. The code provided to Kullback accelerated the work of SIS's weather section, which had independently broken a Russian weather cipher in June 1942 and had been reading encrypted Russian meteorological transmissions since that time. The weather reports provided information useful for American air and maritime operations. For the historian, however, these brief reports, produced by a minor desk at Arlington Hall, have an additional significance. They were the army's first Russian decryptions since the creation of the Signal Intelligence Service, and perhaps the first Russian decrypts by American intelligence since Herbert Yardley read Bela Kun's telegrams to Lenin in 1919. They were also a harbinger.

   In February 1943 the SIS activated a Russian section, although this was done without informing the White House or the State Department. Mysteriously, the section closed two weeks later but was reconstituted several weeks after that. Breaking Soviet codes was a long, arduous task but by mid-1944 four Red Army operational systems were being read. Progress was aided by various "bag jobs"—clandestine raids by FBI agents and others to acquire cryptographic materials from embassy safes. In another mysterious affair, some Soviet-related code materials seem to have been acquired from Finland. Finally, the SIS began collaborating with the British in this area. Ultimately, success was far from complete.

   In the end signals intelligence probably had little impact on American diplomacy toward the Soviet Union in the last year of the war. With Moscow's high-grade diplomatic and military traffic resisting Arlington Hall's attacks, Washington was denied access to the leadership traffic that would have revealed Russian intentions and activities. While useful, third-party traffic (French, Greek, Japanese, Turkish) was modest compensation for the inability to read Soviet communications. Usually this traffic merely confirmed intelligence gleaned from more traditional channels, such as embassy reporting. It is unlikely that it significantly altered the perceptions of policy makers already inclined by experience and current observation to suspect Soviet intentions. Even before Soviet activity began to feature prominently in such reporting channels as the Magic Diplomatic Summaries, senior officials such as Admiral William Leahy (chief of staff to the president), Averell Harriman (ambassador to the Soviet Union), George Kennan (embassy counselor in Moscow), General John Deane (head of the American military mission in the Russian capital), and Loy Henderson (director of the State Department's Office of Near Eastern Affairs) had developed serious concerns about Moscow's ambitions as Russian armies conquered and occupied Eastern Europe. Similar concerns were reported from Bucharest and Sofia by American diplomats in contact with Soviet occupation policies. With the exception of Admiral Leahy, these officials had no access to signals intelligence, but they did not need special sources to alert them to Moscow's intentions toward Poland or Bulgaria or any of the proliferating flashpoints in U.S.-Soviet relations. While signals intelligence would have done little to change their attitudes, it certainly did not form them.

   Through the first two-hundred-plus pages of his book, Alvarez offers what is mostly a social, organizational, and bureaucratic history of the SIS. Given the subtitle of the book, "Codebreaking and American Diplomacy," it seems fair to insist on an answer to the question, "Overall, how much impact did the SIS's successes have on the relevant policy-makers in American foreign affairs?" Up to this point in his book, Alvarez has not demonstrated much impact at all, and has not given a definitive answer to the question.
   Fortunately, the author answers that decisive question as he wraps up his book with a brilliant and revealing discourse on the limitations of sigint within the American government during WWII, and he does so in a manner which suggests even broader implications for the use of signals intelligence. In this final chapter, more than he does anywhere else in the book, Alvarez directly discusses the link between specific decrypted diplomatic traffic and resultant American policy decisions. The examples cited prove to be few and relatively insignificant.

   If signals intelligence ever had an impact on wartime American diplomacy, it was during multinational conferences such as the one in San Francisco. Nevertheless, assertions about the influence of codebreaking on American foreign policy must remain conditional or speculative, even in the case of international conferences. Historians hoping to connect a decrypt or set of decrypts with a particular foreign policy decision will almost always be disappointed. Except in a handful of cases (e.g., Roosevelt's assurances to Stalin in 1942 that Japan would not attack the Soviet Union, and, less certainly, the decision in 1944 to "get tough" with Argentina for its pro-fascist posture), there is no evidence that signals intelligence directly influenced particular diplomatic decisions. On the other hand, in several instances Roosevelt and his diplomatic advisers, buffeted by political necessity, assured by personal conviction or intuition, or constrained by the paucity of viable alternatives, seemingly disregarded the sigint evidence when determining a policy. In 1941 the White House and the State Department clung to the hope that economic sanctions would restrain Japan even though Japanese intercepts clearly indicated that Tokyo would not be deterred by embargoes. After Germany's invasion of the Soviet Union, Roosevelt was not deterred from committing American supplies to Russia by signals intelligence (largely Japanese) indicating that the Soviets would quickly succumb to German attack. The specter of a separate peace between a beleaguered Soviet Union and a triumphant Germany haunted American deliberations over a second front despite consistent evidence from the decrypts that neither Berlin nor Moscow had any interest in a separate peace.
   To conclude simply that decision makers must have rationally and deliberated acted upon available signals intelligence is to confuse the mere existence of intelligence with its influence. This approach begs several very important questions: Did the relevant decision makers all receive the same signals intelligence at the same time? Was that intelligence unambiguous in its meaning? Did the decision makers all place the same credence in that intelligence? Did they all absorb that intelligence to the same degree? Was the available signals intelligence relevant to their decision priorities at any given time? Were there other influences that might have undercut the impact of signals intelligence? The problem is in part one of isolating and weighing any single element among the myriad factors that contribute to a decision. All too often the most that can be said is that sigint may have been one of several factors that influenced a decision or policy. Further complicating analysis is the fact that little is known about the process by which intelligence of any sort was integrated into decision making in the White House and the State Department. What little is known, however, suggests that the arrangements diluted the potential impact of signals intelligence.

   Alvarez then proceeds to explain the very primitive methods by which the intelligence product was prepared and delivered to its customers, methods which almost ensured no one could take full advantage of what they were shown. Little wonder then, that the author concludes sigint was under-utilized and seldom an important aspect of high-level diplomatic decision making.
   Bath's very similar book on naval sigint proved a dry account of naval intelligence and failed to work up much steam. In much the same way, despite Alvarez's valiant attempt to inject interest and importance into Secret Messages, the limited practical impact of the codebreakers' remarkable work can be summarized in the book's closing paragraphs.

   Roosevelt was especially insensitive to the value of signals intelligence. He seems to have considered Arlington Hall's precious product as no more reliable than other forms of intelligence. There is little evidence that sigint engaged his attention, and there is no evidence that he ever specifically asked to see decrypts from a particular target. Content to have a handful of decrypts read to him while he completed his morning toilette or enjoyed and afternoon massage, Roosevelt received (and may have wanted) from the messages little beyond a general sense of that day's intelligence "headlines." This rather cavalier attitude denied him a full appreciation of the source and its importance. Indeed, even after years of receiving signals intelligence, Roosevelt seemed to have only the vaguest notion of what the codebreakers were doing for him. In November 1943, when sigint coverage of Tokyo's diplomatic traffic was practically total and access to Japanese military traffic was increasing dramatically, the president complained to his secretaries of war and navy that the United States was getting "practically nothing from the inside of Japan" and urged Stimson and Knox to secure better information about Tokyo's capabilities and intentions. Characterizing the president's complaint as "a staggering statement given both the quality and quantity of Japanese SIGINT that reached him daily," one historian has concluded that "Roosevelt never seems to have grasped that SIGINT provided him with the best intelligence in the history of warfare."
   The president's failure to grasp the diplomatic advantage proffered by signals intelligence would have marginalized the codebreakers even if their efforts had not been constrained by operational difficulties. Together, the various factors ensured that, for all its expansion and achievement, signals intelligence would have little appreciable impact on American diplomacy in the period 1930-1945.

   Secret Messages shines a bright beam into some of the darker recesses of WWII signals intelligence activities, but ends up illuminating little of critical importance to the diplomatic scene in the Second World War. While Alvarez has done a fine job of researching his topic and piecing together such a thorough account, like most of the work of the codebreakers themselves, this is a book of quiet, steady, persistent study rather than explosive revelations.
   Available from online booksellers, local bookshops, or directly from University Press of Kansas.
   Thanks to UPK for providing this review copy.