The government has promised more and better security at airports following the near-disaster on Christmas Day, but privacy advocates are not prepared to accept the use of full-body scanners as the routine screening system.
"We don't need to look at naked 8-year-olds and grandmothers to secure airplanes," Rep. Jason Chaffetz (R-Utah) said last week. "I think it's a false argument to say we have to give up all of our personal privacy in order to have security."
After each major terrorism incident, the balance between privacy and security tilts in favor of greater security. But in the last decade, privacy advocates have been surprisingly successful in blocking or stalling government plans to search in more ways and in more places.
A conservative freshman in the House, Chaffetz won a large bipartisan majority last year for an amendment to oppose the government's use of body-image scanners as the primary screening system for air travelers. He was joined by the American Civil Liberties Union, which said the scanners were the equivalent of a "virtual strip search."
The pro-privacy stand does not follow the traditional ideological lines; Republicans and Democrats have joined together on the issue now and in the past.
Advocates of increased security are frustrated.
"Privacy and attacks on profiling have been the big hurdles" to developing a better security system for air travelers, said Stewart Baker, who was a top official in the Department of Homeland Security under President George W. Bush.
Since 2001, privacy advocates have twice blocked moves to collect more personal data on passengers and to compile it in a computerized government system. Critics said mass databases would give the government too much information about ordinary Americans. And they said too many innocent people showed up on the watch lists.
At the same time, privacy concerns slowed the move to put more body-imaging scanners in airports. Currently, 19 airports have at least one scanner in use. Now, however, the specter of a man authorities say is a young Al Qaeda convert walking onto a transatlantic flight with a plastic explosive in his underwear has spurred the drive to put the full-body scanners in all the major airports.
The Transportation Security Administration had already announced plans to buy 300 devices, and is likely to purchase more.
The Senate did not adopt the Chaffetz amendment, so the TSA is free to press ahead with installing the body scanners.
"They significantly enhance security because they can detect metallic and nonmetallic items hidden under clothing," said Greg Soule, a TSA spokesman. "And on average, it takes 12 to 15 seconds."
He also suggested that privacy concerns were exaggerated. "It is 100% optional for all passengers," he said. "They can choose to be screened with a full-body pat-down."
Moreover, the screener who observes the passenger's body image is "in a remote location" and cannot see the individual's face, he said. And the body image itself "looks like a chalk etching of a passenger."
Chaffetz disputes that point. He said the body scanners give an explicit view of a naked person. "It is a whole-body image, and they can spin it 360 degrees. And they can zoom in and see something as small as a nickel or dime," he said. "But they can't spot something hidden in a body cavity. A good old-fashioned sniffing dog is more effective."
ACLU lawyers said air travelers should not have to face the prospect of exposing potentially embarrassing medical details, such as colostomy bags or mastectomy scars or their use of adult diapers.
"We continue to think the American people are being sold a bill of goods with these body scanners. Giving the government the authority to scrutinize your body is a tremendous invasion of privacy, and the benefits are questionable," said Jay Stanley, a privacy expert in the ACLU's Washington office.
If the scanners become standard, "the terrorists will adapt to it," he added. "What will we do the next time if someone inserts an explosive in a body cavity and takes it out in the bathroom of the airplane? At some point, we need to draw the line on how much privacy we are willing to give up."
Despite their disagreements, the defenders of privacy and advocates of increased security agree that a better use of information should permit the government to focus its screening on the individuals who pose a threat.
"We clearly need to move faster to a point where we're looking for terrorists, not just weapons," said Baker, a Washington lawyer and formerly general counsel to the National Security Agency. "And the key to that is having more data and using it with more discretion in screening passengers. The current system condemns children and grandmothers to intrusive screening without any assurance it will catch sophisticated terrorists."
He blames Congress, business travelers and privacy advocates for stalling computerized data systems that could alert airport officials to passengers who pose some risk, so they could be given additional screening. Because of past rebuffs in Congress, the Department of Homeland Security "has been quite gun-shy about programs that could be called profiling or data-mining," he said.
Shortly after the Christmas Day incident, Sen. Dianne Feinstein (D-Calif.) called for making it easier to add travelers to a government watch list so they will get extra screening or be denied the right to fly.
President Obama and his top aides also said the government needed to focus more on "high-priority threats" and add names quickly to the no-fly list.
Chaffetz said he strongly supported extra screening -- including the use of a full-body scanner -- if a passenger's name appeared on any of the government watch lists.
"I favor secondary screening for all 550,000 persons in the government database. They should be required to go through a mandatory secondary screening," he said. "If there is some basis for doing a secondary screening, do it. But don't do it for every person. You don't have to screen the grandmother from Boise."