The federal body in charge of airport security is resisting changes to its new body-scanner technology in the face of a media storm of protest that has become the latest issue of the moment for the American right.

Protests about the intrusiveness of the new all-body scanners, and about the manual pat downs that are given to travellers who chose to avoid the scans, has reached fever pitch in recent days. A "National Opt-Out Day" is being organised for Wednesday, one of the busiest flying days of the year on the eve of Thanksgiving.

The protest has the potential to cause considerable delays as the pat-down procedure takes much longer than passing through the scanners.

The federal authorities are trying to stand firm against the increasingly shrill debate about airport security, insisting that the new technology is a necessary balancing act between public safety in the wake of the terrorism threat and respect for individual privacy. In a statement, the head of the Transportation Security Administration, John Pistole, said that refinements would continue to be made to the screening procedures "to make them as minimally invasive as possible while still providing the security that the American people want and deserve".

But he also reminded people of the attempt by the so-called "underwear bomber" to blow up a jet over Detroit last Christmas Day and that "the terrorists allegedly behind the thwarted cargo attempt last month are out there bragging about how they will strike again".

The furore over the body scanners and pat downs is another example of the changing focus of conservatism in the US. Since 9/11 the emphasis of conservatism was heavily weighty towards security, and more libertarian voices stressing the freedom of the individual were drowned out.

Now those voices have been given renewed clout as a result of the Tea Party movement that has had a strong libertarian streak.

The current pat-down controversy has, like the Tea Party generally, been given huge impetus by the rightwing media. Fox News has been leading on the subject, as has the Drudge Report which for several days has been dominated by links to airport security horror stories.

Those have included the story of Cathy Bossy, a breast cancer survivor, who opted out of the body scan only to be told to remove her prosthetic breast during the pat down. Then there was Thomas Sawyer who was covered in his urine after a pat down tore the urostomy bag that he carries as a result of bladder cancer.

Further anger has swirled around video footage of a young boy made to take his shirt off during a pat down that has gone viral on YouTube.

Against that, the TSA points out that fewer than one in five of the 2,100 security lanes in US airports are equipped with the new body scanners, and even in those cases pat downs are rarely administered should an alarm be sounded or the traveller opt out of the screening process.