The disappearance last week of a Transportation Security Administration hard drive that contains personal data on 100,000 TSA employees has raised the frightening prospect that terrorists might soon be able to identify the undercover air marshals who toil to keep our skies safe.

With their brush cut hair, bull necks and oh-so-casual Dockers attire, air marshals have never blended in too well. They're the serious looking chaps who board planes early. But letting their names, birth dates and Social Security numbers walk right out of TSA headquarters in Arlington, Va., boggles the mind. This is the agency that's supposed to screen crazies from getting on planes?

"When you can't even secure computers inside TSA, it kind of makes you wonder," said Sen. Pat Leahy (D-Vermont) at a Senate Judiciary hearing on Tuesday.

A federal criminal probe into the hard drive theft is underway. The FBI and Secret Service are helping out. Apparently, the TSA is unsure whether the drive was stolen or simply lost. TSA administrator Kip Hawley downplayed the threat to air marshals yesterday. But some law enforcement experts see it differently. It wouldn't require much effort to use information from the drive to identify and track down air marshals.

"There are grave security concerns here," said Bruce Schneier, an information security expert testifying before Congress this morning.

At least TSA's web designers have their $#*% together. The agency quickly worked up a slick flash presentation about the incident. The effect is kind of like having someone scream at you repeatedly that everything is under control. Sure. We believe you.