Jackalope Pursuivant takes off from my post yesterday about Pearl Harbor. If I were to give it a theme, I would call it "shock of the new." From time to time folks, for example in the military, may say that they understand a new technology, but the fact that a few smart staff officers "get it" does not mean that the military has really adjusted itself to it. Like any large organization, it has a culture and set of expectations and people who have been successful based on the old model of things. They may say they understand that naval aviation has changed things, but they don't really adjust themselves until Pearl Harbor and Clark Field and Guam and Singapore are full of smoking ruins of planes and ships.
Dan's observation about how quickly the US dusted itself off and recognized that the world had changed is a good one. One could argue that no one did this in WWI. The Europeans had every chance to see what the machine gun could do even before the war in a few African wars. Heck, the final year of the American Civil War around Petersberg was a preview of WWI, as was the ill-fated charge of the light brigade. But armies were still dominated by cavalries and plumed hats and bayonet charges and elan vital. Even in 1916 and 1917, when they should have learned their lesson, commanders were still obsessed with making full frontal charges. The Americans had the chance to watch the war for four years before they entered, and then promptly began committing the exact same mistakes based on the exact same faulty assumptions as in 1914. (Neal Stephenson has a great take on American flexibility to craft radically new combat doctrine based on new facts in WWII in Cryptonomicon, absolutely one of my favorite books).
As for Pearl Harbor, I am reminded of a quote that was attributed to Frank Borman (at least in the From the Earth to the Moon documentary) when he was testifying about the Apollo 1 fire. He called it "a failure of imagination" -- no one was even thinking about danger on the ground, all the focus was on space. At the end of the day, the ultimate answer for Pearl Harbor's negligence in readiness was a failure of imagination. They may have had war games and studies discussing Pearl Harbor attacks, and they may have addressed the possibility intellectually, but no one in command really believed that a couple of hundred aircraft would suddenly appear over peacetime Honolulu dropping bombs and torpedoes.