@Cruiser, I believe that the Japanese military strategists who launched it thought that the Pearl Harbor attack (plus Philippines, plus Indochina, because they were all more or less simultaneous) would cripple our will to fight as much as, maybe even more than our ability. The USA was perceived by those militarists as slothful, indolent and decadent – which was even partly true – but like Hitler thinking that the USSR just needed “to have its door kicked in” to collapse – it was a stunningly huge misapprehension of the foe.
Most wars, apparently, are based on these kinds of fundamental miscalculations of the enemy. Don’t forget, at the same time they launched their attacks (plural) we never widely believed the Japanese to be even capable of such strategic precision, not to mention to mention “military strength” to mount the kind of attack that the Pearl Harbor task force alone represented. And this even 35 years after Tsushima, the surprise attack on Port Arthur, home base of the Russian Pacific Fleet in 1905.
That miscalculation continued all through the war, when Americans believed the Japanese to be ‘suicidal’ in their refusals to surrender in the face of overwhelming force, and Japanese regarding American surrenders as ‘dishonorable’ – which helps to account for some of their treatment of POWs.