By the time John Brennan got down to his underwear, travelers in the Portland, Ore., international airport had begun to gather, snapping photographs on smartphones and gawking. It’s not every day a guy takes off all his clothes in the middle of an airport screening.

But the 49-year-old high-tech consultant didn’t notice, he says, having entered a kind of Zen-like trance as he peeled off one layer of clothing and then the next, undoing each button one at a time, until there was nothing left to remove but his skivvies. Brennan ran his thumb along the elastic and looked at the Transportation Security Administration supervisor.

The supervisor looked at him:

“Don’t.”

But Brennan did, which is how he wound up in handcuffs, an airport holding cell, newspaper headlines, on a few major news networks and, he hopes, into a serious discussion about what he considers to be the sham that is airport security; the TSA as the emperor without any clothes, as it were.

He swears he wasn’t really thinking that far ahead last month, when he declined to submit to a body scan and the resulting pat-down led to a screener swabbing his clothing with one of those explosives-detecting swab thingies and supposedly detecting nitrates, a common ingredient in certain kinds of bombs. At the time, Brennan told The Daily Beast, he was thinking about the flight he needed to catch to San Jose for a business meeting, about how ridiculous he felt it was for anyone to suggest he might be hiding explosives on his body, and how he had a little extra time before takeoff to make a point.

Brennan, like any good Portlander, has participated in his share of organized World Naked Bike Rides and is well versed in the state law that allows people to be nude, provided they’re not somehow getting off on being nude (which would make it indecent exposure). He’s also aware that a guy arrested in June 2008 in one particular naked ride had a Multnomah County judge clear him of indecent exposure. So when the TSA told him something on his clothes tested positive for nitrates, he figured he had every right to rip off his clothes and prove otherwise. Middle of the airport or not.

“I’m not carrying a bomb,” he told the guards as he undressed. When they told him to put his clothes back on, he refused.

“I said ‘I believe I am within my rights to be naked as a form of protest,’” Brennan said. “Not too long after that, I find myself naked in handcuffs.”

Brennan was arrested and eventually charged with indecent exposure. He could cop a quiet plea and emerge from the legal system with a minor citation, but this is one political voyeur who is determined to use his birthday suit to make a point. He intends to fight these charges and, in doing so, generate as much publicity—and debate—about what he deems the completely unnecessary abdication of civil liberties we’ve all come to passively accept in America, given that the TSA’s screening procedures actually accomplish very little, other than to make people irritated and uncomfortable.

“It’s security theater,” Brennan said. “They know it doesn’t do anything, but it gives the appearance of doing something. The TSA needs to justify itself and the billions of dollars they’re spending. They need to do their job, and I felt I needed to do my job, which is protecting my civil rights.”

The TSA is still “assessing” the incident, a spokesman told The Oregonian, and could still decide to seek up to $11,000 in civil penalties for interference with the screening process.

“TSA partners with the traveling public to screen all passengers safely and efficiently,” the agency said in a statement. “When a passenger chooses to be purposefully disruptive, we notify law enforcement.”

The new president of Brennan’s fan club is Kate Hanni, executive director of flyersrights.org, an airline-passenger advocacy group based in Napa, Calif. She has spent countless hours picking apart TSA security procedures, and Brennan has inspired her to think about ways more people might use their own areas where the sun don’t shine to call attention to the airport-security-as-hoax issue.

“I’d like to put together some kind of holiday protest, possibly on the Fourth of July, if I can get enough people to do it,” Hanni told The Daily Beast. “I was thinking teenagers in kilts, with nothing underneath. And they all opt out of the scanners.”

Everybody gripes about airport security, but Hanni and Brennan are two who believe that what we sacrifice when we remove our shoes and belts and jackets and allow some stranger to see what we look like with our clothes off or some other stranger to fondle us if we refuse that option isn’t worth the so-called security we get in return.

For one thing, there’s the well-known problem that airport security is always responding to the last threat. After a guy tried to blow up a plane with a bomb in his shoe in 2001, we had to start taking off our shoes. When a plot developed to blow up a plane with liquid bombs disguised as soft-drink bottles in 2006, we had to start giving up (most of) our liquids. When somebody figured out how to cram a bomb into his underwear in 2009, we went to full-body scans.

So, what terrorist in his or her right mind would try any of those approaches today in order to blow up an airplane? No terrorist, of course. You get past security by figuring out what they aren’t checking for, what their scanners don’t detect.

Take a “cavity bomb,” for example: explosives hidden in rolls of fat, between butt cheeks. Those fancy body scans may show how round your nipples are, but they don’t go deeper than a half inch or so. They can’t detect cavity bombs, Hanni insists. Only an X-ray could do that, and even Americans as jittery about terrorism and gullible about how to stop it probably wouldn’t accept an X-ray every time they board a plane.

It’s this irony, this outrage, that relieved Brennan of his clothing last month.

“I didn’t snap,” he said. “I snapped to my senses.”

He’s not some nudist freak who just likes having people size up his package. He is a person who believes mightily that we are allowing our civil liberties in America to be eroded for no good reason. He gets choked up when the conversation about the airport “debriefing” reaches this point, this heart of the matter. He may have disrobed that day without a lot of premeditation and forethought, but he’s spent many an hour contemplating this insanity that is getting on an airplane in the year 2012.

“I just felt like they went too far,” he said.

But, what’s the TSA to do? If they find traces of nitrates on a guy’s fleece, are they supposed to just shrug and wave him through? Brennan doesn’t really have an answer for that, but it’s beside the point, he insists. The point is that airport screenings have never successfully prevented a terrorist attack, and that there are far more effective ways to keep bad guys from doing bad things on airplanes.

Ask Israel, which has the Rolls-Royce of airport screening operations. They don’t maintain a 100 percent success rate by patting people down or taking intrusive pictures or making people take off their shoes. They train screeners (imagine that!) to ask smart questions, and how to identify suspicious answers, anxiety, hostility. They meet people as they’re getting out of their cars. They watch how travelers handle their bags.

“They also have facial recognition machines they use to scan through databases of known terrorists,” Hanni said. “You have a better chance of finding even a lone wolf by assessing behavior.”

That al Qaeda attack thwarted by CIA spooks in Yemen a few days ago? It was likely Ibrahim Hassan al-Asiri’s answer to the failed underwear bomb, Version 2.0, without metal parts, with a more sophisticated triggering device. “Probably” not detectable by a metal detector; unclear whether the new body scanners would have caught it.

Those body scanners, by the way? It just so happens that former Homeland Security secretary Michael Chertoff was running around urging everyone to install them in the wake of the first underwear bombing attempt, which worked out nicely for the Chertoff Group, his security consulting agency, which represents Rapiscan, a manufacturer of many of the machines. And those companies making the scanners have more than doubled their spending on lobbying in recent years to make sure lawmakers keep voting to put them in airports.

The way to stop terrorists from getting aboard airplanes is to detect terrorists, not by groping grannies and Donald Rumsfeld because a hip replacement set off a buzzer in a machine, Hanni says.

John Brennan hopes this truth is now laid bare.