The terror attack of September 11, 2001 was quite literally off the charts: no other single act of terrorism has ever done remotely as much damage. Over the course of the entire 20th century, fewer than twenty terrorist attacks managed to kill as many as one hundred people, and none killed more than four hundred. Until September of last year, far more Americans were killed in any given grouping of years by lightning than by all forms of international terrorism combined. Of course, such data beg the central question of the post-9/11 world: Will we revert to the relatively benign levels of the past, or have we really entered a new and nasty era?
Most observers hold to the latter, believing that the September 11 attacks represent a sort of historical step functionâ€"the â€œeverything has changedâ€ point of view. Accordingly, they suggest that such extensive destruction to life and property will become common or even routine, particularly if the United States and its allies fail to respond vigorously to the threat. This is hardly a baseless supposition. It is clear that the convergence of certain political and technological trends gives such concerns real logical traction. However, a case can be made that rather than foreshadowing the future, the attacks may turn out to have been a statistical outlier, a kind of tragic blip in the experience of American national security.