American here. I consider myself an amateur historian. I've recently started dating a woman who was born and raised in Canada. She claims that she was taught in school that the Pearl Harbor attack was deliberately allowed to happen by the US government in order for the US to wage war. At first I couldn't believe that this was being taught in school. But then it got me thinking... Am I wrong here? Is there any hard evidence to back up her claims?
It's a myth. FDR knew there was almost certainly an attack coming in the near future, and the US had overheard encoded Japanese messages that in retrospect could have given a pretty good indication that it was Pearl Harbor being attacked, but the cryptography units of the Army/Navy (they were splitting the duties because of inter-service rivalries) didn't get around to decoding the relevant messages until after the fact. As you might guess, the cryptography units suddenly got a lot more funding and attention post-Pearl Harbor, but even then they were relatively small. There was no CIA, NSA, etc. at that point, just the fairly small intelligence units within the military branches.
Recommended: Christopher Andrew, For the President's Eyes Only