When the Transportation Security Administration dispatched undercover investigators last spring to test the effectiveness of airport checkpoints, the results were deplorable. Agents posing as passengers were able to smuggle weapons and mock explosives through 67 out of 70 TSA checkpoints — a failure rate of 95 percent.

Following that debacle, the TSA’s acting administrator was given the boot, and the Department of Homeland Security announced that it had “immediately directed TSA to implement a series of actions, several of which are now in place, to address the issues raised in the report.”

That was in June. In July, a new TSA chief pledged to lawmakers that within 60 days “we will have trained the failure out of the front line” of airport screening personnel. So how do things stand four months later?

The House Oversight and Government Reform Committee held a hearing on that question last week, with Homeland Security Inspector General John Roth as the key witness. Roth reported the findings of a new round of undercover testing at US airports, and he didn’t beat about the bush.

“The test results were disappointing and troubling,” he said. “The results were consistent across every airport. …The failures included failures in the technology, failures in TSA procedures, and human error. We found layers of security simply missing. It would be misleading to minimize the rigor of our testing, or to imply that our testing was not an accurate reflection of the effectiveness of the totality of aviation security.”

In short, yet another fiasco. And the government’s response? Yet another directive from Homeland Security that “an immediate plan of action be created to correct deficiencies uncovered by our testing.”

Fourteen years after the creation of the TSA, there is still no indication that the agency has ever caught a terrorist, or foiled a 9/11-type plot in the offing. Conversely, there are reams of reports documenting the inability of TSA screeners to spot hidden guns, knives, bomb components, and other dangerous contraband as they pass through airport checkpoints. It’s doubtful that anyone is still capable of being surprised by a fresh confirmation of the TSA’s incompetence — even if members of Congress do sometimes feign alarm for the sake of the folks back home.

Let’s face it: The Transportation Security Administration, which annually costs taxpayers more than $7 billion, should never have been created. The responsibility for airport security should never have been federalized, let alone entrusted to a bloated, inflexible workforce. Former TSA administrator Kip Hawley calls it “a national embarrassment that our airport security system remains so hopelessly bureaucratic” and warns that “the relationship between the public and the TSA has become too poisonous to be sustained.” More tests and more failures won’t fix that. Scrapping the TSA would.

Fearmongers might howl, but abolishing the agency wouldn’t make air travel less secure. Given the TSA’s 95 percent failure rate, it would likely make it more secure. The airlines themselves should bear the chief responsibility for protecting planes and passengers at airports. After all, they have powerful financial incentives to ensure that flights are free of danger, while at the same time minimizing the indignities to which customers are subjected. Their bottom line would be at stake. The TSA feels no such spur.

Effective defense against airline terrorism doesn’t require patting down grandmothers or confiscating eyedrops. It requires sophisticated counterterror intelligence (which is what stopped the 2006 liquid bomb plot), and it calls for passengers to be vigilant (which is what ultimately foiled the underwear and the shoe bombers). The TSA supplies neither, and its enormous budget could be put to far better use.

It has frequently been observed that the rigmarole at US airports provides not security, but security theater — a show designed to make travelers feel safer without actually enhancing their safety. At $7 billion a year, that makes the TSA the most extravagant theatrical production in history. Isn’t it time to bring the show to a close?

Jeff Jacoby is a columnist for The Boston Globe.