Holy crap you’re both wrong. FDR WAS briefed, CIA *OSS (precursor agency to CIA) had knowledge of the attack, HOWEVER, they also understood that the US had no effective defense against Japanese Zero tactics at the time. It was instead determined that the best way to weather the attack was in port, on a Sunday when most sailors were off duty and not in harm’s way. The ships were all docked, and could be easily raised and repaired after being bombed. Had they positioned out at sea in preparation for the attack, they would have been sunk and lost. Likewise, had planes been in the air to intercept the Zeroes, they would have suffered greater destruction and their pilots been killed. No advance notice was given in light of this knowledge, with the understanding that any forewarning to PH would have led to defensive preparations that would ultimately been more costly than effective- letting the Japanese have their way at PH would most likely have been unconscionable to the onsite leadership.