We have reason to wallow in a moment of pride. Cooperation between Pakistani, British, and American law enforcement agencies foiled a plot to bring down a number of airliners. This saved countless lives and was a clear victory for the good guys.

But a few things are worthy of note. This victory was achieved by the police, not the military. Further evidence that the real war on terror has less to do with armored humvees and small artillery, and more to do with intelligence and surveillance. It’s also important to recognize that while this was a victory, many of the same agencies failed to find the plot which destroyed the British subway stations last year. This is also the reality of terror plots. Some will succeed, no matter how hard we try.

Does that mean we shouldn’t try? Absolutely not. We must remain vigilant. We must fund every means of legal electronic and human surveillance to stay ahead of these groups. We should support small military incursions to disrupt the ability of these groups to organize and train. And we must take reasonable precautions in our own lives to identify and prevent terror plots. But what constitutes a “reasonable precaution”? And why are we so twitchy about airplanes? And why are we so good at screening for plots that have already happened, and so bad at anticipating new ones?

In the wake of the latest plot, airlines have banned all liquids and gels from being carried on board. Why now? Acetone peroxide (the liquid chemical explosive planned in the airline plot) was the same chemical used in last year’s British subway bombing. The chemical is stupidly easy to make. It’s kitchen chemistry. It’s also dangerously unstable, but this isn’t much of a deterrent for a would-be suicide bomber. And this is hardly the only easy to make home explosive. I can accept that prior to 9/11 we lacked the imagination that someone would use a plane itself as a projectile weapon. But given the obvious danger of explosives on planes, how much imagination did it require to think that someone might use an explosive they could make in their kitchen from products that can buy at the corner drugstore? Clearly, this was a case where the probable danger didn’t warrant the hassle, inconvenience, and frankly the futility of trying to prevent it.

As an example, the current prohibitions make exceptions for prescription drugs where the drugs are in their original bottle and issued to the person named on the ticket. Acetone peroxide can also be made into (or purchased as) a powder, which is reasonably stable in small quantities. How hard would it be to empty drug capsules and replace the contents with explosive powder. An in-flight trip to the rest room would provide an opportunity to empty all the capsule contents into a single container. This IED does not even require a detonator. It will explode upon physical shock. It could be thrown and explode on contact.

Most of the airport security is designed to make you feel safer more than it is to make you safe. Do you recall the spate of incidents a few years ago showing that our security leaks like a sieve? A Transportation Department test found that screeners missed 30% of guns, 60% of simulated explosives and 70% of knives. I personally travel with a small Leatherman-like tool in my bag. It has a small blade which is illegal by the current regulations. However, because of the way the tool folds, it has never been caught by x-ray screening. I lose it occasionally when I get selected for a random bag search, but that’s the only time.

The point is that there is no 100% guarantee of safety on airplanes. Curiously, we accept this reality on trains. Despite train bombings in Spain (2004), England (2005), and India (2006), we still blissfully get on commuter trains in crowded cities most every day. Surveillance has increased, but no one requires you to remove your shoes and surrender your Diet Pepsi prior to boarding the subway.

So let’s not over react here. Security is a good thing when done usefully and thoroughly. But as a dog & pony show it’s just inconvenient and demeaning.