For a while, there has been a contrarian school of thought in historical study of WWII that FDR, wishing to have the US enter the way against a strong isolationist streak in the general population, purposefully ignored evidence of an impending Japanese attack at Pearl Harbor in order to create a casus belli. A few historians have used some intelligence warmings combined with the insane un-preparedness of Pearl Harbor as their evidence. Instapundit links to a new declassified memo that warns of Japanese interest in Hawaii just three days before the attack.
This is a fun but generally foolish game. The same game was played after 9/11, pointing to a few scraps of intelligence that were "ignored." But the problem in intelligence isn't always lack of information, but too much information. In late 1941, the US government was getting warnings from everywhere about just about everything. It is easy as a historian to pick out four or five warnings and say they were stupidly (or purposely) ignored, but this fails to address the real point -- that those warnings were accompanied by a thousand false or misleading ones at the same time. The entire Pacific theater had already had a whole series of alerts in the months leading up to Dec 7, one false alarm after another. It is Monday morning quarterbacking that strips the intelligence problem of its context. To prove that something unusual happened, one would have to show that these warnings were processed or prioritized in a manner that was unusual for the time.
And sure, the readiness issue at Pearl Harbor is inexcusable. But while historians can always find a few people at the time who argued that Pearl Harbor was the most logical attack target, this ignores the thousands in and outside the military who thought the very idea of so audacious an attack that far from Japan was absurd. Historians are failing in their job when they strip these decisions of context (if you really, really want to get on someone about preparedness, how about McArthur, who allowed most of his air force to be shot up on the ground despite having prior notification of the Pearl Harbor attack hours before).