how sad and true

Not exactly. In every administration, there are tons of military and intel analysts studying world political and military situations and producing reports on what they think will happen. It is very tough to sort through all this data and figure out which is most credible. It's like Bush before 9/11: they had an idea something was going to happen, but they had no idea of what or where. Many military leaders of the day didn't think Japan was capable of attacking Hawaii. I do think FDR did do some things to provoke the Japanese, such as the embargoes, but I don't think he purposefully let the attack happen just to get us in the war. I'm no fan of FDR, but I don't think he was involved in some vast conspiracy.

I don't believe that one vauge memo would have changed the outcome. If we knew of the time/date of the attack, we could have met the Jap's head on which would have saved American lives and resources. A Japanese armada headed to Hawaii loaded for an attack would have been as great an act of war as the actual attack.
And I'm like Steve2112, FDR was one of the worst presidents we ever had. It took that war and the hundred million killed to bring us out of the depression he could do nothing about dispite all his socialist handouts and jobs. I would rank him as the worst President of the last century, even below LBJ and Carter.