Did FDR deliberately allow the Pearl Harbor attack ?

This is a question that has raged for many years, and its answer has come forth only after the deaths of virtually every govt. & military official in power when the attack occurred.

That answer is: THE BLAME FOR UNPREPAREDNESS FOR THAT ATTACK MUST BE SHARED BY MANY !
First, there was an almost-universal contempt for Japan's military prowess. They were viewed as having inferior equipment, being a lot less in population & resources than us, & being physically & mentally inferior to us. Our boys paid no attention to their modern ships & aircraft, & especially their optics, their determined character, their eyesight & hearing being equal to ours, & the fact that a small man can shoot as well as a large man, while presenting a smaller target. They didn't believe Japan would commit "national seppuku" by attacking us.

Second, as relations deterioriated between the nations, it appeared that Japan would attack the Philippines or Malaya if they attacked anyone at all, or they'd possibly attack Russia if German victory seemed imminent over Russia.

The US govt. didn't know Japan was in a hurry to create the "Southeast Asia Co-Prosperity Sphere" & saw the US oil embargo, brought about by Japan's activity against China, as a huge threat to her military capability. Meanwhile, the US wanted to drag out negotiations to end this embargo long enough to complete a large military buildup in the Philippines to serve as a deterrent to Japan's attacking there or Malaya.

Before relations deterioriated, then-Sec. of State henry Stimson declared, "Gentlemen do not read each other's mail", referring to the Intelligence Depts. of the govt. & military, thus resulting in both those intel orgs being understaffed. When relations deterioriated, there was a vast volume of radio intercepts pouring into those orgs, resulting in a backlog of deciphering and evaluations of their significance. Still, there was little indication of the planned PH attack. However, early in 1941, Sec. of Navy Frank Knox had sent a letter to now-Sec. of War Stimson, advising him thatanj attack on PH was very possible, & that defenses against air attack were lacking. Stimson forwarded that letter to Gen. Walter Short, Commander of Hawaii air defense, & Adm. Husband Kimmel, Pacific Navy Commander. here is where Short & Kimmel's share of the blame comes in. Knox had even accurately advised that PH was vulnerable from the north, which was where the attack came from, & that recon should be stepped up there. However, neither Short nor Kimmel beefed up that recon, being more-concerned with possible sabotage by the large Japanese population of Hawaii.

But those 2 commanders were not apprised of ANY intel suggesting an attack pn PH might be imminent, still being told that Japan would likely attack in a place much-closer to Japan. There had been frequent "imminent war alerts" sent out by the govt. so those commanders had become a little jaded to them, but even when indicators had begun to come in that PH might be attacked, they were NOT advised ! (Putting a base on full war alert costs $$, & the commanders didn't want to waste money when attack didn't seem imminent.) Thus, they were caught with their pants down by the attack.

The Intel Depts. also had to choose what was important to send to FDR for immediate attention, & were usually a few days behind due to the aforementioned understaffing & the vast volume of intercepts. Thus, FDR was not aware of the impending PH attack, either. Also, the Japanese were successful in dispatching their carriers for the attack without being detected.

When news of the attack came to FDR's attention, he immediately acted with great dispatch in ordering the mobilization of all our military. Later that day, he learned that the attack had come BEFORE Japan had declared war, and his anger over that was evident in his speech to Congress asking for a declaration of war.

Yes, the blame must be shared by the top military command, & the Depts. of State & War. They under-estimated Japan's ability to wage war, & had inadequate intel orgs to keep up with events. While it was well-known FDR was highly-sympathetic to Britain, he certainly didn't deliberately allow the PH attack to occur as a causus belli for an excuse to join Britain against the Axis.

 

I believe I found the most-reliable sources, next to the actual transcripts of the intercepts of Japanese radio traffic, most of which are still boxed upstairs in the National Archives.

The reason so much of that traffic was classified was to protect the reputations of many of the officers & bureaucrats involved. Both Short & Kimmel had been very-able officers before the attack, but they were made scapegoats for the attack in the great game of PTOA that occurs in govt. & military when something goes wrong. (Look at all the excuses made after the space shuttle disaster.)

As I said, Short & Kimmel bear SOME blame for being caught off-guard, but certainly not the MAJORITY of it. More falls on the Joint Chiefs-of-Staff, & on the bureaucrats of the State & War Depts.

Far as FDR goes, he was advised daily about the progress of negotiations with the Japanese diplomats. And, as I said earlier, the intel brought to him was often several days old due to the sheer volume an understaffed intel org had to sift through. And Japanese pre-planning played no small part. Their plans were in place, so no radio traffic at all had to be used when the carriers set sail. And the Japanese used the carriers' known call signs when they were actually talking to other ships that had been told of their "new" call signs. Remember, the Japanese had been planning this attack for some time before launching it, so it went almost like clockwork. (However, after the attack, some of their codes had been recovered by the USN from a downed plane, leading to better deciphering of their further plans.)

Somebody simply told your dad wrong. (My dad was in the ETO & didn't know much about the Pacific war.) As you said, the story has been around for 79 years, & it was much-hotter in 1946 than it is now.

 

The civilian USA powers-that-were then were actively negotiating with the Japanese diplomats to attempt to reach a modus vivendi, that is, a temporary arrangement both sides could live with til a more-permanent settlement could be reached. However, on Nov. 26 or 27, some intel reached FDR, presumably about a Japanese troop convoy that had left Shanghai, apparently heading for Thailand. This intel was rumored to have come from Churchill. (It was no secret Churchill wanted more American help, & FDR wanted an excuse to provide it.) Soon after, the American delegation presented a plan they knew the Japanese wouldn't accept, that included a complete withdrawal from China. Thus, negotiations ended, for then.

The USA was on war alert then, as they knew Japan had no real alternatives with their oil supply from the USA cut off, which would soon immobilize their military. However, they shortly re-opened negotiations in one last attempt to prevent war.

All indications were pointing to a Japanese attack against Malaya, the Philippines, or Thailand. The USA under-estimated Japan's ability to conduct simultaneous attacks, & there was no recent intel pointing to an attack on PH. The USA tried to rush more bombers to the Philippines to deter Japan from starting a war; they were still doing that when they attacked PH. Yes, the USA was on war alert, but in the wrong area !

However, Japan made a HUGE mistake ! the attack was supposed to come AFTER a declaration of war, but their Dept. of Diplomacy messed up, & their US Embassy was slow in deciphering the war declaration message, so that declaration wasn't presented to the USA until AFTER the PH attack weas over. That fueled the massive amount of anger against Japan, as it turned the PH attack into a SNEAK attack, in much the same manner as Germany had attacked Russia. Just about every American still living will tell you that the fact of a sneak attack made them work that much harder against Japan.

There's no doubt that Yamamoto was horrified when he learned of the diplomatic SNAFU. There's some doubt that he uttered the words, "I fear all we have done is to awaken a sleeping giant and fill him with a terrible resolve" but some of his staff said he did indeed make that statement. He had studied at Harvard & had been posted in the USA for several years, & knew American nature & capability quite well. He knew the Americans would fight extra-hard because of the sneak attack.

 

The declaration of war wasn't handed to Mssrs. Stimson & Hull until a full 1.5 hours AFTER the PH attack had occurred. The times were recorded by their offices. The declaration arrived about 1430 hrs. while the attack began 1248, EST, Washington DC time. Hull had been informed before he met with the Japanese diplomats, who didn't know about the attack themselves, & were surprised at his angry demeanor toward them. Those Japanese had no advance warning of the attack, either. (At least our govt. arranged for them to safely leave the country.)