Periodically, people ask Goldblog, who plays the role of TSA Answer Man when my colleague James Fallows isn't playing TSA Answer Man, why the Marine Air Terminal at LaGuardia airport in New York is not equipped with the advanced scanners the TSA deploys at other, less sensitive airports. (Jack Shafer was the first one to point this out to me.) In my Bloomberg View column this week, I discover the answer:

The TSA deploys two types of advanced passenger- screening machines in U.S. airports: Millimeter-wave whole- body imagers and so-called backscatter X-ray devices, both of which can detect non-metallic objects under a person's clothing. These very expensive machines are crucial to the TSA's protocol, which is why it strikes me as strange that the security checkpoint at the Marine Air Terminal goes without one, and instead relies on an old-fashioned metal detector.
On busy days, more than a dozen flights are dispatched from the Marine Air Terminal to Washington's Reagan National Airport, which, as anyone who has flown there knows, is mere seconds by air from the White House and the U.S. Capitol (as well as TSA headquarters, it should be noted). Why would the federal government not equip this particular terminal with its most advanced machinery? The answer is both banal and telling.

Click here to read more.

By the way, Vanity Fair has an interesting piece now up about a visit to an airport with the security guru Bruce Schneier. I wish I had thought to do this!