On the first day of random searches in the New York City subway, Police Commissioner Raymond Kelly reported that they "actually had people who came over and volunteered to have their bags checked." The New York Times located one such individual, a 35-year-old woman named Eve Holbrook, at a station in Brooklyn. Having a police officer paw through her belongings gives her "a sense of comfort," she said. "I went up there of my own free will."

 I don't pretend to understand Holbrook's motivation: Did she think she might have accidentally slipped a bomb into her briefcase that morning? But if letting police look in their bags makes people feel better, who am I to question it?

 That, at any rate, seems to be the general attitude toward New York's new search policy, which has been copied in New Jersey and may soon be imitated in Washington, Boston and San Francisco. It's hard to see how it will prevent a terrorist attack, but it makes people feel safer.

 New York's subway system provides nearly five million rides on the average weekday. The city is not releasing precise figures, but the Times reports police are searching "thousands" of bags a day. Even allowing for the fact that not every rider carries a bag, the chance that any given bag will be selected for a search is minuscule.

 "Anything we can do to introduce uncertainty will make it harder for the adversary to figure it out," a RAND Corporation terrorism expert told the Times. No doubt that's true, but in this case the added uncertainty is negligible.

 In the highly unlikely event that a terrorist with a bomb is selected for a search, he can simply say no and exit the system with no questions asked. It has to be that way if the city is going to argue in court that the searches are voluntary (a dubious claim, given how important the subway is to the average New Yorker).

 Upon leaving the subway, a terrorist unlucky enough to be picked for a bag check can try again at another station, hand his bag off to an accomplice, or detonate his bomb at a crowded location above the ground. It should not be hard to find one in New York City.

 But if the illusion of security won't fool the terrorists, at least it fools the public. "I see it also as giving some comfort to the riding public," said Commissioner Kelly. "Reassuring the public is a legitimate objective," said RAND's terrorism expert. "You might say, dismissively, it's just to make people feel better. But we shouldn't dismiss it."

 I think we should, and here's why: If any measure that is ostensibly aimed at preventing terrorism is justified, whether or not it actually prevents terrorism, simply because some people believe it will prevent terrorism, we might as well forget about our constitutional rights and start lining up behind Eve Holbrook. Continued...