I’d recommend reading two serious books on the subject:
Infamy by Toland
https://www.amazon.com/Infamy-pearl-harbor-its-aftermath/dp/042509040X
and
At Dawn We Slept by Prange
https://www.amazon.com/At-Dawn-We-Slept-Untold/dp/0140157344
Toland makes the case that President Roosevelt knew there would be an attack, that he wanted an attack to take place, and he did not exert much effort to prevent an attack.
To sum up, my interpretation of the case made is: we knew there would be an attack, probably on December 7th. We did not know exactly where, but there were indicators it would be Hawaii at Pearl Harbor. Toland tries hard, but there is no absolute, black letter proof President Roosevelt knew, in advance, the attack would be at Pearl Harbor. There are lots of inferences such could have been the case.
Prange takes the opposite camp and says we did not know, and goes into detail about all the things we should have done, but did not do if we had known. He does not cover the time before the attack anywhere in the detail Toland does. To sum up Prange:
We did not know about the attack, but it does not matter because we needed the attack to happen. We had to get into the war, and this was the best way to do it.
My take is: President Roosevelt understood an attack was very likely. He probably was not absolutely certain it would be at Pearl Harbor. He probably did not think the Japanese were capable of as much destruction as they dished out. He definitely wanted the Japanese to attack first to get us into the war.
Both good reads. Could recommend quite a few more, from inside Naval Archives. Henry Stimson’s diaries for example, and the book most often cited for the so called “conspiracy theory” is the one by Robert B. Stinnett in response to the Prange book.
Stinnett followed with 17 years of research and the publishing of his book, “Day of Deceit-The Truth about FDR and Pearl Harbor”. Quite revealing. Won’t go any further in the discussion. Without details, family took the message “Attack- this is no Drill” on board 6 hours out of Pearl Harbor, in a vessel which had already sunk some japanese shipping between Pearl and Midway— in October. Will leave it there.
The subject matter leaves a bad taste— sort of like LBJ’s completely FAKE as hell Silver Star for combat he never took part in (him and Connally, thanks to their buddy Nimitz). Tiresome lying prongs— both of them- typical machine demonrats.
The U.S. government made nine official inquiries into the attack between 1941 and 1946, and a tenth in 1995. They all have been critiqued (often from a very political point of view massaging facts, etc.)
This response is useful, thank you for putting a source to my post.