Last fall, Condé Nast Traveler aviation correspondent Barbara S. Peterson applied to work as a Transportation Security Administration screener. Her mission: to investigate reports that despite a five-year, $20 billion overhaul of the passenger screening system, checkpoint personnel are failing at the job. Being hired was only her first surprise. Peterson's two months at the airport revealed how this overtaxed but dedicated workforce copes with equipment shortages, budget cuts, and record numbers of (not very pleasant) passengers. Here is an unprecedented look at the reality of America's last line of defense

In September and October of last year, I worked for the Transportation Security Administration as an airport screener-in-training. To protect the privacy of my former co-workers, I have altered the names of the screeners mentioned in this story and have not identified the airport where I worked.

It is 6:30 a.m. on a Wednesday in October. This should be a slow day at the airport, but we are one week into the new security regime—a thicket of regulations designed to eliminate the bomb-making potential of heretofore innocent items ranging from mascara to infant formula—and things are not going smoothly. In August, authorities in London uncovered a plot by a group of terror suspects to take down half a dozen airliners using liquid explosives camouflaged in beverage containers. Immediately, all liquids were banned from flights. Now, more than a month later, the Transportation Security Administration has come up with a convoluted compromise, permitting each passenger a liquid allowance. Confusion reigns: A mass of passengers creep toward the checkpoint in stocking feet, juggling shoes, carry-ons, computers, and plastic bags containing doll-size bottles of shampoo and other toiletries.

I am manning the walk-through metal detector and simultaneously keeping an eye on what some of us mockingly refer to as "the pen," a makeshift holding area for the unfortunates who've been selected for further scrutiny. I've learned two things about this task since I joined the ranks of TSA screeners a month ago: You can't predict who will be picked for a more thorough inspection, and there's no good way to break the news to them.

A woman on crutches hobbles through the portal and hands me her boarding pass, which bears the dreaded code. "Ma'am," I stammer, "you've been selected for, uh …additional screening." Behind her wait her four children toting bulging backpacks, each with a boarding pass that indicates they too will need to be inspected.