A gift to Pearl Harbor conspiracy theorists (13 nov 13)
I visited Bletchley Park, home of the WWII codebreakers, birthplace of computers, in 2012. My pictures of it are here.
I'd never looked through its website before though. It's not written from the point of view of strict historical accuracy.
Not only that, it contradicts itself:
"Nor were the Germans the only targets for Station X - by breaking Japanese ciphers, the Codebreakers were able to monitor the Japanese preparations for war. The suggestion that they knew of the imminent attack on Pearl Harbor but kept quiet in order to ensure America joined the war is nonsense. But their expertise undoubtedly gave great assistance to the American codebreakers." - http://www.bletchleypark.org.uk/content/hist/worldwartwo/impact.rhtm
So... they'd cracked the Japanese military ciphers by December 1941. They were thus able to monitor the Japanese preparations for war. But they didn't know of the imminent attack on Pearl Harbor. And to suggest they did, is "nonsense". No it isn't.
I once saw a talk about the great Pearl Harbor conspiracy by author Robert Stinnett - the idea that Roosevelt knew the Japanese were coming and let it happen to scare up support for war. I wasn't very convinced, and still am not. But the above passage from Bletchley Park is the basis of a more plausible conspiracy theory.