Six years after the terrorist attacks of 2001, airport security remains a theater of the absurd. The changes put in place following the September 11th catastrophe have been drastic, and largely of two kinds: those practical and effective, and those irrational, wasteful and pointless.

The first variety have taken place almost entirely behind the scenes. Explosives scanning for checked luggage, for instance, was long overdue and is perhaps the most welcome addition. Unfortunately, at concourse checkpoints all across America, the madness of passenger screening continues in plain view. It began with pat-downs and the senseless confiscation of pointy objects. Then came the mandatory shoe removal, followed in the summer of 2006 by the prohibition of liquids and gels. We can only imagine what is next.

To understand what makes these measures so absurd, we first need to revisit the morning of September 11th, and grasp exactly what it was the 19 hijackers so easily took advantage of. Conventional wisdom says the terrorists exploited a weakness in airport security by smuggling aboard box-cutters. What they actually exploited was a weakness in our mindset — a set of presumptions based on the decades-long track record of hijackings.

In years past, a takeover meant hostage negotiations and standoffs; crews were trained in the concept of “passive resistance.” All of that changed forever the instant American Airlines Flight 11 collided with the north tower. What weapons the 19 men possessed mattered little; the success of their plan relied fundamentally on the element of surprise. And in this respect, their scheme was all but guaranteed not to fail.

For several reasons — particularly the awareness of passengers and crew — just the opposite is true today. Any hijacker would face a planeload of angry and frightened people ready to fight back. Say what you want of terrorists, they cannot afford to waste time and resources on schemes with a high probability of failure. And thus the September 11th template is all but useless to potential hijackers.

No matter that a deadly sharp can be fashioned from virtually anything found on a plane, be it a broken wine bottle or a snapped-off length of plastic, we are content wasting billions of taxpayer dollars and untold hours of labor in a delusional attempt to thwart an attack that has already happened, asked to queue for absurd lengths of time, subject to embarrassing pat-downs and loss of our belongings.

The folly is much the same with respect to the liquids and gels restrictions, introduced two summers ago following the breakup of a London-based cabal that was planning to blow up jetliners using liquid explosives. Allegations surrounding the conspiracy were revealed to substantially embellished. In an August, 2006 article in the New York Times, British officials admitted that public statements made following the arrests were overcooked, inaccurate and “unfortunate.” The plot’s leaders were still in the process of recruiting and radicalizing would-be bombers. They lacked passports, airline tickets and, most critical of all, they had been unsuccessful in actually producing liquid explosives. Investigators later described the widely parroted report that up to ten U.S airliners had been targeted as “speculative” and “exaggerated.”

Among first to express serious skepticism about the bombers’ readiness was Thomas C. Greene, whose essay in The Register explored the extreme difficulty of mixing and deploying the types of binary explosives purportedly to be used. Green conferred with Professor Jimmie C. Oxley, an explosives specialist who has closely studied the type of deadly cocktail coveted by the London plotters.

“The notion that deadly explosives can be cooked up in an airplane lavatory is pure fiction,” Greene told me during an interview. “A handy gimmick for action movies and shows like ’24.’ The reality proves disappointing: it’s rather awkward to do chemistry in an airplane toilet. Nevertheless, our official protectors and deciders respond to such notions instinctively, because they’re familiar to us: we’ve all seen scenarios on television and in the cinema. This, incredibly, is why you can no longer carry a bottle of water onto a plane.”

The threat of liquid explosives does exist, but it cannot be readily brewed from the kinds of liquids we have devoted most of our resources to keeping away from planes. Certain benign liquids, when combined under highly specific conditions, are indeed dangerous. However, creating those conditions poses enormous challenges for a saboteur.

“I would not hesitate to allow that liquid explosives can pose a danger,” Greene added, recalling Ramzi Yousef’s 1994 detonation of a small nitroglycerine bomb aboard Philippine Airlines Flight 434. The explosion was a test run for the so-called “Project Bojinka,” an Al Qaeda scheme to simultaneously destroy a dozen widebody airliners over the Pacific Ocean. “But the idea that confiscating someone’s toothpaste is going to keep us safe is too ridiculous to entertain.”

Yet that’s exactly what we’ve been doing. The three-ounce container rule is silly enough — after all, what’s to stop somebody from carrying several small bottles each full of the same substance — but consider for a moment the hypocrisy of T.S.A.’s confiscation policy. At every concourse checkpoint you’ll see a bin or barrel brimming with contraband containers taken from passengers for having exceeded the volume limit. Now, the assumption has to be that the materials in those containers are potentially hazardous. If not, why were they seized in the first place? But if so, why are they dumped unceremoniously into the trash? They are not quarantined or handed over to the bomb squad; they are simply thrown away. The agency seems to be saying that it knows these things are harmless. But it’s going to steal them anyway, and either you accept it or you don’t fly.

But of all the contradictions and self-defeating measures T.S.A. has come up with, possibly none is more blatantly ludicrous than the policy decreeing that pilots and flight attendants undergo the same x-ray and metal detector screening as passengers. What makes it ludicrous is that tens of thousands of other airport workers, from baggage loaders and fuelers to cabin cleaners and maintenance personnel, are subject only to occasional random screenings when they come to work.

These are individuals with full access to aircraft, inside and out. Some are airline employees, though a high percentage are contract staff belonging to outside companies. The fact that crew members, many of whom are former military fliers, and all of whom endured rigorous background checks prior to being hired, are required to take out their laptops and surrender their hobby knives, while a caterer or cabin cleaner sidesteps the entire process and walks onto a plane unimpeded, nullifies almost everything our T.S.A. minders have said and done since September 11th, 2001. If there is a more ringing let-me-get-this-straight scenario anywhere in the realm of airport security, I’d like to hear it.

I’m not suggesting that the rules be tightened for non-crew members so much as relaxed for all accredited workers. Which perhaps urges us to reconsider the entire purpose of airport security:

The truth is, regardless of how many pointy tools and shampoo bottles we confiscate, there shall remain an unlimited number of ways to smuggle dangerous items onto a plane. The precise shape, form and substance of those items is irrelevant. We are not fighting materials, we are fighting the imagination and cleverness of the would-be saboteur.

Thus, what most people fail to grasp is that the nuts and bolts of keeping terrorists away from planes is not really the job of airport security at all. Rather, it’s the job of government agencies and law enforcement. It’s not very glamorous, but the grunt work of hunting down terrorists takes place far off stage, relying on the diligent work of cops, spies and intelligence officers. Air crimes need to be stopped at the planning stages. By the time a terrorist gets to the airport, chances are it’s too late.

In the end, I’m not sure which is more troubling, the inanity of the existing regulations, or the average American’s acceptance of them and willingness to be humiliated. These wasteful and tedious protocols have solidified into what appears to be indefinite policy, with little or no opposition. There ought to be a tide of protest rising up against this mania. Where is it? At its loudest, the voice of the traveling public is one of grumbled resignation. The op-ed pages are silent, the pundits have nothing meaningful to say.

The airlines, for their part, are in something of a bind. The willingness of our carriers to allow flying to become an increasingly unpleasant experience suggests a business sense of masochistic capitulation. On the other hand, imagine the outrage among security zealots should airlines be caught lobbying for what is perceived to be a dangerous abrogation of security and responsibility — even if it’s not. Carriers caught plenty of flack, almost all of it unfair, in the aftermath of September 11th. Understandably, they no longer want that liability.

As for Americans themselves, I suppose that it’s less than realistic to expect street protests or airport sit-ins from citizen fliers, and maybe we shouldn’t expect too much from a press and media that have had no trouble letting countless other injustices slip to the wayside. And rather than rethink our policies, the best we’ve come up with is a way to skirt them — for a fee, naturally — via schemes like Registered Traveler. Americans can now pay to have their personal information put on file just to avoid the hassle of airport security. As cynical as George Orwell ever was, I doubt he imagined the idea of citizens offering up money for their own subjugation.

How we got to this point is an interesting study in reactionary politics, fear-mongering and a disconcerting willingness of the American public to accept almost anything in the name of “security.” Conned and frightened, our nation demands not actual security, but security spectacle. And although a reasonable percentage of passengers, along with most security experts, would concur such theater serves no useful purpose, there has been surprisingly little outrage. In that regard, maybe we’ve gotten exactly the system we deserve.