Saturday, 15 September 2001 : "unthinkable acts"

Why did so many of them remain in their seats or in the backs of the planes while the hijackers took aim at buildings containing thousands of people? Because it never seriously occurred to those passengers that the hijackers would use the planes for that purpose.

This is one of the most important lessons of Tuesday's catastrophe. Our ability to prevent crimes is constrained not only by technical limits--money, intelligence assets, airport security administration--but also by conceptual limits. We can't prepare for what we don't anticipate. Furthermore, the range of scenarios we anticipate isn't limited merely by what we think others can do. It's also limited by what we think they will do.

After a terrorist attack, everything looks different. You realize that every plane is a potential guided missile and that every hijacker might be a kamikaze pilot. Yet nothing has changed except the range of your imagination.

Where will terrorists strike next? If you've got an answer off the top of your head, it's the wrong answer. To thwart a terrorist, you have to think like one.