When the waves of Japanese dive bombers flew in on Pearl Harbor on Dec. 7, 1941, the good news was that the US Navy had previously sent its Pacific fleet aircraft carriers out to sea. Otherwise, they would have been sunk or damaged at their moorings as the fleet's battleships were. It was those surviving carriers that turned the tables on Japan little more than a half-year later at the Battle of Midway.

The Japanese preemption marked what Franklin Roosevelt called "a day which will live in infamy,'' and in the American memory its character as a sneak attack has signified the height of political immorality. ("Now I know what Tojo felt like,'' Robert Kennedy remarked as he contemplated an attack on Cuba, "when he was planning Pearl Harbor.'')

The American public's rage at the blow's perceived unfairness was such that, had Hitler not "quixotically'' declared war against the United States four days later, it is possible, according to war historian John Keegan, that American forces could have been deployed "en bloc'' to the Pacific.

There is no doubt that Pearl Harbor inflicted a massive national trauma - the date is still marked on calendars - but its meaning transcends the actual scope of the attack, and its character. The emphasis on sneakiness, for example, ignores the ample precedence in war of unannounced initiative.

Indeed, surprise is a normal strategic asset. Japan and the United States had been openly making belligerent moves toward each other: the US Pacific fleet had been transferred from San Diego to Hawaii; US bombers had been forward-based in the Philippines. War readiness was the drill. The intensity of shock was rooted less in Japanese chicanery than in America's race-based assumption of technical and martial superiority. As for morality, the Japanese attack was aimed against genuine military targets. The US revenge attack, a bombing raid led by Jimmy Doolittle on Tokyo some months later, was aimed purely at civilians.

The deeper shock of Pearl Harbor, and why it lives on as a turning point in the American narrative, has to do with its significance as the event that jolted this nation into the wielding of power. Native Americans and Mexicans from whom Washington had forcibly seized much of the continent knew otherwise, but to most Americans it seemed that Pearl Harbor marked the radical shift from innocence to morally complex military engagement.

Leaving behind the ethical purity of isolation, we armed ourselves and entered the global arena to stay - a gladiator nation from then on. A world power. And we learned soon enough, as Reinhold Niebuhr would put it, that there is no exercise of power in the world without guilt. As our revenge assaults on Japan would show, especially at the end of the war, we would have guilt aplenty. The argument from Pearl Harbor on, of course - and no one made it better than Niebuhr - was that the renunciation of power for the sake of innocence involved "even more grievous guilt.''

Pearl Harbor was revived as a milestone in the American imagination on Sept. 11, 2001. Indeed, 9/11 replaced Pearl Harbor as the motivating trauma of American power, but once again the shock was mostly to our sense of national superiority. The anger sparked by the Japanese assault was in direct proportion to the fear it instilled, but in the conventional war that followed there were multiple channels into which that fear could run. Bloody as the battles were, the enemy was readily identified, and definitions of victory and defeat were clear.

Not so after 9/11. Instead of battleships and aircraft carriers, the real danger comes from variations on box cutters and explosive charges hidden in shoes. The revelation is that such small bore threat can frighten a nation as much as an armada. After Pearl Harbor, the scale and meaning of mobilization was crystal clear. After 9/11, with our futile, misdirected, ongoing wars of vengeance, which lay nary a glove on Al Qaeda, the mobilization has mainly been against ourselves.

The Niebuhrian argument about action leading to guilt versus inaction leading to greater guilt seems strangely outmoded because terrorists are unfazed by such distinctions. Our fear remains unchanneled, therefore unchecked. So also our rage. Pearl Harbor was a mark of the good old days.