Closing the book on Pearl Harbor

Cryptologia, Apr 2000 by Budiansky, Stephen

One thread of continuing suspicion and excitement for the conspiracy theorists in search of something stronger, however, has always been the Japanese naval codes. Because of continuing security classification, technical details about the breaking of most Axis codes remained under wraps for a half century, with the first major, wholesale release of documents occurring only in 1996, when the National Security Agency transferred to the National Archives some 5,000 files from Arlington Hall's records. Even now some World War II documents are classified out of exaggerated fears that any discussion of codebreaking methods and techniques, even methods from the pre-computer age, would compromise national security.

The very existence of such a seemingly incomprehensible veil of secrecy, of course, arouses suspicion; and for some time now a number of revisionist authors have been raising the suggestion that what is being hidden is the fact that the United States was routinely reading not only the diplomatic messages but also the operational naval messages of the Japanese fleet before Pearl Harbor. Such operational traffic messages, it is presumed, could not fail to have delivered the goods; unlike the PURPLE traffic, which dealt only with high level diplomatic negotiations, these naval signals would contain orders to the fleet at all levels, and would surely have betrayed to even the dimmest intelligence analyst the object of Japan's military intentions.

Robert Stinnett now claims to have unearthed evidence that that was indeed the case. His book Day of Deceit (Free Press, $26.00) received a huge amount of prepublication hype, with plugs from Gore Vidal on the back cover and in the Nation,2 among other things. Stinnett recycles all of the arguments familiar to readers of the Pearl Harbor revisionists, but adds what the publisher terms an "explosive" revelation. Examining "an extraordinary number of documents whose release I have been able to engineer through Freedom of Information Act requests," the author writes, he has determined that "by the closing the months of 1941, America was intercepting and breaking-within a matter of hours-most every code that Japan could produce. . . The truth is clear: FDR knew."

Stinnett's assertions about the Japanese naval codes are the crux of his thesis, and his only real claim to advancing the conspiracy narrative beyond its familiar limits, and so it is worth a close examination of the evidence that the United States had indeed penetrated the naval codes long before the officially acknowledged date of spring 1942.

The most immediate difficulty with Stinnett's contention is that it has been directly and repeatedly contradicted by the testimony of the U. S. naval officers whose responsibility it was to break the Japanese codes. Stinnett brushes this problem aside easily enough: they were "lying" or "part of the cover up"-a "sixty year cover up [that] has hidden American and Allied success in obtaining the solutions to the naval codes before Pearl Harbor." Well, you can't have a conspiracy without conspirators, so perhaps we should grant him this point for the sake of argument.