In Robert Heinlein's 1951 campy science fiction classic "The Puppet Masters," alien slugs invade Earth and take over human minds by attaching themselves to people's bodies and sucking the free will from them like drinking a milkshake through a straw.

With the alien menace spreading like a plague, it quickly becomes a matter of survival to tell the robo-humans from those who remain slug-free. The problem is that the slugs hide inside people's clothes, making it difficult to tell whether a U.S. senator was under alien mind control or merely a self-serving dunce.

Heinlein's solution: People get naked. Once the authorities determine that modesty is giving the slugs an edge, clothes go out the window and birthday suits become proper attire in public places. Those who don't expose themselves are considered indecent.

Fast-forward to 2010 and in place of alien slugs you have radical jihadists. Like the vermin from Titan, they yearn to control others. And if blowing up a passenger-filled airliner helps the cause, as Umar Farouk Abdulmutallab is accused of trying to do last month in Detroit, they're prepared to do what it takes to smuggle explosives aboard.

To me it's a no-brainer. If the best way to keep airliners safe is to require passengers to strip, that's what you do. You don't like it, you don't fly.

Fortunately, the technology now exists that ensures the public will not have to let it all hang out. The latest generation of security scanners - four of which are installed at Baltimore-Washington International Thurgood Marshall Airport - can create a whole-body image that, in effect, looks under the clothing and detects concealed items such as the pouch of explosive powder that found its way into the would-be martyr's underpants on Christmas Day.

The images are revealing. In my case, it would show a definite need to lose weight.

Folks from all shades of the political spectrum have objected to the use of the technology in spite of its effectiveness. The favorite phrase of the opponents appears to be "virtual strip search."

So? A virtual strip search makes perfect sense. It combines the thoroughness of a physical examination with the convenience of being virtual. No intrusive hands pawing you, no need to disrobe. It might not reveal every conceivable threat - it still can't see inside the body - but it's far superior to what's in place now.

Bill Toohey, the former Baltimore County Police spokesman, wrote me as a private citizen about his recent experience with the technology while traveling with family.

"Last month on a trip to Ann Arbor, Michigan out of BWI, I was selected to go through that new body scanner. I didn't know why, but I was singled out to go stand in this clear booth, hold my hands over my head, and then turn around. It took maybe 15 seconds. The TSA officers were polite and professional, but no one told me what this was about. I figured I might be going through the body scanner, which I had heard about.

"My one impression about it was that it was quick, and painless. And quite honestly, what really struck me is how transparent it is - literally. In reading about this system in the past I thought it would be some sort of enclosed space, with metal walls. But this was not the case. It is almost all clear glass, and you never feel cut off from what is going on. I could see everything around me, and, for me at least, there was nothing claustrophobic."

According to the TSA, what was happening out of Toohey's sight was this:

A security officer at a location outside the terminal - far from the eyes of Toohey's fellow fliers - was watching the screen and seeing the ghost-like image of a human form with all the prurient value of a dental X-ray. The screener could have determined that the subject was male but he could also tell that the passenger was not concealing something dangerous in places that pat-down searchers usually avoid. The officer would have had no clue whose body he was viewing because the face would be a blur.

For now, the high-tech imaging machines at BWI are used for secondary screening of randomly selected fliers or those who might have raised some red flags. At several U.S. airports they are being tried out as the first line of defense, but there are moves afoot in Congress to prevent such use. In June, the House voted 310-118 to prohibit the use of whole-body screening as the default security measure.

If all House members who voted "aye" were put through a scanner, it seems unlikely that more than a few of them would be found to be under the sway of alien parasites. Scientific illiteracy, suspicion of government and political prudishness are more probable explanations for their denial of reality.

One can only hope the events in Detroit prompt the Congress to back off and let the TSA aggressively roll out the most effective screening technology at our disposal. If they don't, the slugs win.