In thinking about the significance and consequences, a decade and a half later, of the terrorist attacks known as 9/11, it is best to begin with what the attacks did not mean — despite what voluminous commentary ever since the event might lead one to believe.
The attacks did not mark a major change in security threats faced by the United States or anyone else. Americans were not suddenly more in danger on Sept. 12, 2001 than they had been on Sept. 10, even though the reactions of many Americans would suggest that they were.
Nor was one spectacular, lethal and lucky shot to be equated with a larger threat that can be thought of in strategic terms, or with sudden revelation of such a threat. Those whose job was to assess such things, including those in U.S. officialdom, hadcommunicated prior to 9/11 their clear understanding of the strategic threat represented by Bin Laden’s variety of international terrorism.
September 2001 did not mark the advent of a substantially greater vulnerability of the U.S. homeland, and certainly not an existential one. The techniques involved were not at all comparable in that regard to the introduction of the long-range bomber and the intercontinental ballistic missile.
Nor did September 2001 mark the beginning of serious counterterrorist efforts by the United States, notwithstanding the larger amount of resources thrown at the problem in the wake of 9/11. There was a lot of counterterrorism going on before, especially in the 1980s and continuing into the 1990s.
The available tools and elements of counterterrorism have remained essentially unchanged from those earlier periods, apart from a few technological developments such as those involving unmanned aerial vehicles.
The biggest changes brought about by 9/11 instead involved public perceptions and emotions, and consequently the political treatment of subjects that those perceptions and emotions involved. The politics riding on public fears have been far more consequential than any external reality about what terrorist groups are up to. And much of the public perceptions have been inaccurate, as indicated by the way those perceptions about terrorist threats changed from Sept. 10 to Sept. 12.
Even the public perceptions about terrorism have not been a one-way progression. There has been some of the same swinging of the pendulum of public preferences as seen after previous major terrorist incidents. Although the swing after 9/11 was substantially higher than usual, we have already seen some of the pendulum’s return in the opposite direction.