But like I've been sayin', the USA had cracked a fraction of the Japanese military code while the British had fully cracked it and were not passing on the info. Indeed, Churchill's intelligence briefings are still classified, 75 years later.
Hmm. Now why would that be, eh?
Additionally, no decrypts have come to light of JN-25B traffic with any intelligence value prior to Pearl Harbor, and certainly no such has been identified. Such breaks as recorded by authors W. J. Holmes and Clay Blair Jr., were into the additive tables, which was a required second step of three (see above). The first 100 JN-25 decrypts from all sources in date/time order of translation have been released, and are available in the National Archives. The first JN-25B decrypt was in fact by HYPO (Hawaii) on 8 January 1942 (numbered #1 up JN-25B RG38 CNSG Library, Box 22, 3222/82 NA CP). The first 25 decrypts were very short messages or partial decrypts of marginal intelligence value. As Whitlock stated, "The reason that not one single JN-25 decrypt made prior to Pearl Harbor has ever been found or declassified is not due to any insidious cover-up... it is due quite simply to the fact that no such decrypt ever existed. It simply was not within the realm of our combined cryptologic capability to produce a usable decrypt at that particular juncture."
Detailed month by month progress reports have shown no reason to believe any JN-25B messages were fully decrypted before the start of the war. Tallied results for September, October, and November reveal roughly 3,800 code groups (out of 55,000, about 7%) had been recovered by the time of the attack on Pearl Harbor.
...Other information that is still currently classified includes key reports in Churchill's records, including the PREM 3 file in the UK's Public Records Office, which contains Churchill's most secret wartime intelligence briefs. In it, the 252 group dealing with the Japanese situation in 1941 is open, save for the omission of Section 5, dealing with events from November 1941 through March 1942, and is marked with official finality as "closed for 75 years." Unlike the Magic intelligence files released by the United States, none of the Ultra intelligence files pertaining to Japan have been released by the British government.
[source : Pearl Harbor advance-knowledge conspiracy theory, Wikipedia, https://en.wikipedia.org/wiki/Pearl_Harbor_advance-knowledge_conspiracy_theory, Accessed: 12th December 2016]]
FDR may well have wanted some kind of attack, perhaps a patrol boat sunk, something like that, but not on the scale of Pearl Harbor. But Paul Watson's hero Churchill didn't give a f**k! It was only 3000 Americans to get the USA into the war to save the British Empah!