Looking back over my NSA post and discussing it with some non-techie friends of mine, I can see that folks who aren't regular Ars readers may mistake the post for some sort of defense of the administration's spying activities. For the record, I'm one of those "privacy nazis" (we used to be called "conservatives") that people like Michelle Malkin love to hate, and I view any kind of domestic spyingautomated or notwith hostility.

But aside from my general knee-jerk anti-government reactions against this program, there's an even deeper criticism that can be leveled against casting such a wide, computer-automated net. The problem is not that such large-scale industrial fishing invariably catches a few dolphins along with the tuna, but that between 99.999 and 100 percent of what you're going to get is dolphin.

Just imagine, for a moment, that 0.1% of all the calls that go through this system score hits. Now let's suppose the system processes 2 million calls a day. That's still 2,000 calls a day that the feds will want to eavesdrop ona very high number, and still much higher than any courts could possibly oversee. Furthermore, only a miniscule fraction of the overall total of 2 million calls per day on only a few days of each month will contain any information of genuine interest to the feds, and the odds that some of those calls will be among those that catch the governments interest are passing slim.

How slim, you ask? Here's where the real problem with this scheme lies: the odds that a particular terrorist's phone call will rate enough hits to sound an alarm are not primarily dependent on factors that we have control over, like the amount of processing power and brain power that we throw at the task, but on factors that we have no control over, like how good that terrorist is at hiding the content of his communication from the feds. And when it comes to the human ability to speak in "code" so that one audience hears one thing while another audience hears another, we're fighting millions of years of evolution.

As the TSA, with its strip-searching of people's elderly grandparents, abundantly proves every holiday season, blunt instruments and scorched earth tactics are of dubious value in catching genuine bad actors. In fact, blunt instruments and wide nets are the easiest for professional bad guys to evade. All you need to beat such surveillance tools is patience and know-how. This is true for face recognition, it's true for biometrics, it's true for RFID, and it's true for every other high-volume automated technique for catching bad guys.

So what are we as a nation to do? Proponents of mass surveillance tactics will argue that innocent people should have nothing to hide, and that if eavesdropping on millions of innocent peoples' phone calls prevents another 9/11 (or worse, a nuclear attack) then the intrusions were well worth it. When asked just how far they're willing to go to catch the next Mohammed Atta, they'll answer "all the way." When asked how many innocent people they're willing to see flagged by the system in order to catch that one bad guy, they'll answer "as many as it takes." And thus the debate devolves into some nightmarish either-or scenario, where America has a choice between either the end of privacy or the loss of a major city to a catastrophic terrorist attack. But it doesn't have to be that way.

Targeted human intelligence has always been and will always be the best way to sort the sharks from the guppies (to change fish metaphors). Government money invested in much less intrusive and much less defense contractor-friendly programs like training more Arabists and developing more "human assets" in the field will be orders of magnitude more effective than mass surveillance could ever be. Blunt instruments like airport facial recognition software and random subway bag searches produce much more noise than they do signal, and any engineer or computer scientist worth his or her salt will tell you that an intelligent, targeted, low-tech approach beats a brute-force high-tech approach every time.

There is no high-tech substitute for human intelligence gathering. In fact, anyone who's read Malcolm Gladwell's Blink will know that an overload of crudely processed information is actually more likely to lead an analyst astray than it is to produce any useful insight. Limited amounts of high-quality information combined with old-fashioned expertise always has been and still is the only way to sort the real from the fake, whether you're talking about Greek statues or Al Qaeda communications.

In the end, brute force security techniques are not only corrosive to democratic values but they're also bad for national security. They waste massive resources that could be spent more effectively elsewhere, and they give governments and countries a false sense of security that a savvy enemy can exploit to devastating effect.

I'll wrap this post up with a story that shows just how old, and just how ineffective, brute force "search and seizure" tactics are, even when the field has been narrowed using intelligently selected criteria.

A Greek religious text from antiquity tells of a king who got word that a potential usurper to his throne had been born somewhere in his kingdom. He wanted to find this baby and kill it, but the unwitting human assets that he was using to lead him to the child's location got wind of his intentions and managed to slip away. So all the king knew was the sex of the child (male), the city where the child was born, and a rough estimate of the child's birth date. Targeted human intelligence having failed him, he decided to try the brute force approach. He had all the male children in that city that were two years of age or under killed.

After the slaughter of all of those infants, the king sat back in relief. The child could never have escaped that massacre! His kingdom was safe. But unbeknownst to the king, his plan hadn't worked. In spite of the fact that the king had narrowed his search using perfectly sound criteria, the boy and his parents still managed to escape to Egypt, and all of those other children died for nothing. And to top it all off, the boy Jesus wasn't even a real threat to Herod's throne. It was a false alarm! Herod, in his paranoia, had misinterpreted the original intelligence data as pointing to a threat, but in reality it signified no such thing... which brings me to my final point: it's not just enough to have sound intelligence; you also need political leaders who have the wisdom to use that intelligence appropriately.