Monday, November 02, 2009


Homeland security

Via Bruce Schneier, we get an essay by Deirdre Walker, a former Assistant Chief of Police (Montgomery County, MD), about TSA searches and security. Please go read the essay; it’s worth the time.

Ms Walker says a number of important things, but there’s one particular kernel that I want to pick out, that I think is especially important to think about. It’s in these two sentences, which put the whole thing into perspective:

We have asked TSA to find the tools terrorists use and prevent both from boarding a passenger plane. We have unintentionally created an agency that now seeks efficiency and compliance more than any weapon or explosive.

That the first resulted in the second is due to a severe misapplication of basic principles. It comes from a desire to have people see that something was being done, rather than acceptance that the right way to do it is to work barely visibly. This is what happens when we turn what should be serious investigation done backstage... into a showy spectacle. This is what happens when we exchange true protective measures for publicity stunts.

Ms Walker mentions taking off shoes during the airport security check. Now, on the surface, I don’t really mind taking off my shoes. It takes little time. But I mind it because it’s entirely ineffective. It’s useless, and it’s being promoted as a useful tool in the anti-terrorist toolbox. Not one terrorist has been caught, not one terrorist act prevented, not one terrorist weapon found by having us take our shoes off.

The proponents of shoe-doffing, of course, and of our search techniques in general, will argue that we can’t know how many incidents we’ve deterred. How many shoe-bombs might have been used against us had we not scared those wielding them off with our security measures?

And that is certainly a problem with this sort of thing: how do you measure its effectiveness? The absence of a rare event — in this case, a once-ever event, a singleton — isn’t evidence that it’s been prevented. And even if it were, we can’t assume causation. But how can we possibly do any real experiments with security checks? We could certainly make people take off their shoes at some airports, and not at others. We can allow people to carry large shampoo bottles onto some flights, and not onto others. We could accept pocket knives or cigarette lighters on some flights, and not on others. And none of that would tell us anything.

Because apart from the questionable ethics involved, the fact is that all of the threats those mechanisms are defending against are theoretical; none of them has ever happened. No one has ever attacked a flight using the contents of a shampoo bottle, nor with a small pocket knife, nor with a cigarette lighter. And no one has successfully detonated his shoe.

And as the search-supporters say that proof that this is all effective comes from the lack of hijackings, we’re told that proof that the whole system works to make us safer is that nothing like 9/11 has happened since 9/11.

Only, nothing like 9/11 had happened before 9/11 either. And even if we stipulate that our security measures have made it harder to attack airplanes or to use them for attacks, it’s clear that there are many other mechanisms for attack. Taking down two large buildings in a showy manner, and crashing a third plane into the Pentagon, made a major statement. But the real terrorism would come from whittling away at our everyday freedom. It’s not so much a question of fear on entering a large building — which we might have a hope of protecting — but fear that you can’t go into a pizza joint, a deli, or a coffee shop without risking getting blown up. Fear that you can’t ride a bus without taking your life into your hands. It’s not the killing of 3000 people at once that’s truly terrifying, but the killing of 30 people at a time, or even 3, and doing it every day and everywhere.

And that’s not happening here.

It’s a good thing, too, because that, we’re doing little to stop. Because we haven’t created a system for finding terrorists and keeping ourselves safe. We have instead created a system that seeks efficiency and compliance more than any weapon or explosive.

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