Fighting the last battle

What security measures to take against the threat of terrorism? The problem is that there is an almost endless number of ways in which a terrorist act can be carried out, and it is very hard, and probably impossible, to find ways of preventing every possible such plot. Perhaps inevitably, security measures are always reactive. Terrorists hijack four planes, kill three thousand people, and make George Bush win an election, all just with box cutters. Hence all box cutters and pointy objects are banned from flights. A would-be suicide attacker tries to detonate explosive hidden in his shoe. Hence we must X-ray all passengers' shoes. Female terrorists hide explosive in their bras. Hence the stories of passengers being indicently patted during security checks. Today we learn of the explosives to be made out of liquid chemicals. Now no liquids can be taken aboard US flights.

It is only a matter of time until a terrorist tries to smuggle explosive on an airplane by hiding it up his ass. And that's when I am going to stop flying.