Happy birthday, TSA.

The federal agency charged with protecting the nation’s transportation systems turns 10 Nov. 19. And although its supporters will probably spend the coming days talking about its apparent successes, including the absence of a 9/11 sequel, the question of whether we’re better off with this fledgling $8 billion-a-year federal agency remains very much unanswered.

Maybe it’s a good time to ask it. Not only has the Transportation Security Administration been with us for a decade, but it’s also the one-year anniversary of the unpopular pat-down rule, when officials arbitrarily decided to either send air travelers through its new body scanners or frisk them. A citizen-initiated petition on the White House Web site encouraging the government to eliminate the agency is gaining momentum, having collected more than 30,000 signatures.

So what are the TSA’s major achievements? Greg Soule, an agency spokesman, offers a list that includes the TSA’s quick formation after the Sept. 11, 2001, attacks and the fact that no major terrorist incidents have happened on its watch. “Through significant improvements to our processes and technologies, as well as the ongoing professionalization of our workforce, transportation systems are safer now than they ever have been,” he says.

Several experts who have been supportive of TSA policies in the past agree that the agency has done a respectable job during its first decade.

“The TSA’s greatest accomplishment is treating transportation security like the serious, professional, your-life-depends-on-it law enforcement job that it is,” says Mary Schiavo, a former inspector general with the Transportation Department and now a lawyer in Mount Pleasant, S.C.

She says air travelers have forgotten pre-9/11 airport security, which was run by the airlines and was porous and shoddy. Do we really want to return to that? “The airlines allowed 9/11 to happen,” Schiavo says. “They caught [9/11 hijacker] Mohamed Atta at Boston Logan Airport on May 11, 2001, knew he was photographing, filming and watching the security checkpoints at the airport, and they let him go.”

Frank Cilluffo, director of the Homeland Security Policy Institute at George Washington University, says the TSA deserves recognition for adapting to meet the terrorist threat since its creation in 2001. When it comes to aviation security, he says, there’s no quick and easy fix, and the agency’s approach of building a layered defense and using intelligence underpinned by technology and a well-trained workforce is keeping air travel safe.

But other TSA watchers aren’t so quick to label the agency a success. Steve Lord, the director of homeland security and justice issues with the Government Accountability Office, thinks the TSA is a “work in progress.”

It has made significant improvements in some areas but is “still trying to meet other key goals, such as meeting the congressional mandate to screen inbound air cargo,” he says. “Also, they need to adopt more risk-based screening measures to deploy resources more effectively. A one-size-fits-all approach is inefficient and tends to frustrate the traveling public.”

Some experts are more critical. Rich Roth, the executive director of CTI Consulting, a Germantown firm that specializes in aviation security, says the TSA has been “a miserable failure” at one of its unstated goals from the beginning: making travelers feel that they’re more secure than they were under the private screeners that the agency replaced.

Clark Ervin, who was the Department of Homeland Security’s first inspector general and now directs the Aspen Institute Homeland Security Program, thinks the TSA’s biggest shortcoming is its slowness in adopting cutting-edge technology to make air travel safer. “Generally, such technology is deployed after security threats have materialized and not beforehand,” he says.

But when the discussion moves from the theoretical to the practical — that is, when I talk to air travelers about the TSA and its achievements — the responses are a little less diplomatic.

Although many passengers are grateful to the agency for protecting them and are generally supportive of its efforts, the federal screeners have no shortage of vocal detractors. Sommer Gentry, a math professor from Annapolis and an outspoken agency critic, believes that in the past decade, the TSA has made air travel miserable. She says the agency has a legacy of rude employees, nonsensical rules and violating passengers’ privacy.

“Over 10 years, the TSA’s demands have become more and more offensive to a normal person’s sensibilities,” Gentry says. “After each new outrage, the TSA simply refused to acknowledge legitimate criticism, refused to subject its procedures to any cost-benefit analysis, and somehow travelers seemed to resign themselves to more and more debasement.”

Frequent agency critic Bruce Schneier agrees that passengers have simply rolled over. The TSA, he claims, “has turned airplane passengers into sheep.”

And so, as the TSA marks its anniversary with what I’m told will be a brief reflection on its accomplishments, what’s the answer to the question of whether it’s worth keeping?

I’m terribly biased. I’ve been covering the agency since the beginning, and we haven’t always gotten along. The agency has on various occasions lied to me, threatened me and even served me with an illegal subpoena in an effort to persuade me to reveal the name of a source. (I declined.)

If anyone has a reason for wishing that this agency would go away, it would probably be me. And yet I’m not entirely convinced that eliminating the TSA would be the smartest move.

I’m deeply skeptical of the agency’s suggestion that it has somehow prevented another act of terrorism. And although the TSA has never been anything less than professional when I’ve flown, I agree with the detractors who say that it seems to operate above the law and with virtually no accountability to the taxpayers who fund it.

All that’s certain is that we haven’t had another 9/11 in the past decade. Would that also have been true without the TSA? Possibly.

Perhaps the only thing I can say for sure is this: We should never stop asking ourselves whether we’re better off with the TSA.

After all, we’re not all sheep.