Until presented proof otherwise, I’ll maintain for those saying FDR, George Marshall and Cordell Hull had a unique foreknowledge of a Pearl Harbor attack requires looking backwards and piecing together specific data points to prove their thesis. They have had to ignore the fact that these men were living out history forwards. The information the country received from traffic analysis, informants, investigations, and code braking swam in a sea of 10,000’s of data points each month. Remember a few years ago you could buy pictures that seemed a mass of random color pixels, but a single picture emerged if you stared at it in the right way? In this case a host of pictures emerged each week. To make some sense of this data it had to fit probable alternatives.
The population of the probable (in the fall of 1941 we had too few resources to deal with the possible as well) had to fit into War Plan Orange and the corresponding Japanese plan, which was generally known to the U.S. Both plans envisioned the supreme naval battle would be fought in the Western Pacific. Both navies were disciples of Alfred Thayer Mahan who wrote the outcome of war at sea would always be decided by the “decisive naval battle”. Past history had borne that out at Trafalgar, Tsushima, and Jutland. For Jutland Churchill said, “Jellicoe was the one man who could have lost the war in an afternoon”.
When Yamamoto proposed his radical departure from Japanese strategic principles only his firm commitment to resign at a meeting in October 1941 sealed the deal. The Naval General Staff could either find a new commander of the fleet at this late date, or accept his radical departure from existing plans.
In this country Plan Orange continued to determine the most probable interpretation to place on intelligence and events. That may have been an important factor for ignoring the implication of the data point called the “bomb plot” message. In September 1941 the U.S. decrypted a message sent to the Japanese Honolulu consulate asking for reports of ships anchoring or tying to wharves in five specific areas. Some thought this a departure from the ordinary while others thought this a normal interest in ship movements that could help them understand how quickly the fleet could sortie for that “decisive naval battle”.
It seems that only after the war started were men appreciated who could think outside normal channels. In the Pacific I think of men like Nimitz, Rochefort, and Doolittle.
(1) The extent to which FDR and the highest levels of the US armed forces recognized that an attack on Pearl Harbor was both possible and a risk that had to be prepared against;
(2) What warnings of the impending attack, if any, were delivered to FDR and other relevant decision-makers; and
(3) The degree, if any, to which these warnings were deliberately ignored and suppressed by FDR and his associates so that a sudden Japanese attack on Pearl Harbor would assure that the US would enter WW II with a sense of unity and resolution in spite of powerful isolationist sentiments among the American public.
You argue that an attack on Pearl Harbor was not seen as plausible because it was contrary to US and Japanese war plans. The historical record is otherwise. By January of 1941, an attack on Pearl Harbor was feared at the highest levels of the War Department and the Navy and the Pacific Fleet was so informed. The essential documentation was collected and preserved as Exhibit 40 of the Hart Inquiry.
The opening passage of the first letter in January of 1941 to the Secretary of War from Secretary of the Navy Frank Knox makes abundantly clear that a surprise Japanese aerial attack on Pearl Harbor was seen as a distinct possibility:
The security of the U. S. Pacific Fleet while in Pearl Harbor, and of the Pearl Harbor Naval Base itself, has been under renewed study by the Navy Department and forces afloat for the past several weeks. This reexamination has been, in part, prompted by the increased gravity of the situation with respect to Japan, and by reports from abroad of successful bombing and torpedo plane attacks on ships while in bases. If war eventuates with Japan, it is believed easily possible that hostilities would be initiated by a surprise attack upon the Fleet or the Naval Base at Pearl Harbor.
In my opinion, the inherent possibilities of a major disaster to the fleet or naval base warrant taking every step, as rapidly as can be done, that will increase the joint readiness of the Army and Navy to withstand a raid of the character mentioned above.
The dangers envisaged in their order of importance and probability are considered to be:
(1) Air bombing attack.
(2) Air torpedo plane attack.
(3) Sabotage.
(4) Submarine attack.
(5) Mining.
(6) Bombardment by gun fire.
Defense against all but the first two of these dangers appears to have been provided for satisfactory.
My we take point 1 as established between us, that the risk of a surprise carrier attack on Pearl Harbor was in fact recognized well before December 7, 1941?