Today, the busiest travel day of the year, the Transportation Security Administration will introduce many Americans to a new indignity and offense to privacy.

If select airline passengers don’t want TSA agents to review denuded images of their bodies, they can “opt out” and suffer intimate pat-downs at the hands of these strangers. Public opposition to this Hobson’s choice is building. An Internet-organized “National Opt-Out Day” has been planned.

Whatever happens with the protest, the question remains: Is the TSA overreacting to the threat?

Yes. TSA is overreacting. That’s exactly what Congress asked it to do — and it’s exactly what terrorists want Congress to ask for. The better approach now is no change to domestic air security from the status quo of a year ago.

Here’s an interesting statistic: In 99 million domestic flights over the past decade, transporting seven billion U.S. travelers, there have been zero bombs snuck on to planes and detonated. (The one failed attempt came from overseas.) Common sense calls that a risk that’s near zero.

But the media and political imperative — the box we’re in after last Christmas’ attempted bombing — demands something be done. With the strip/​grope policy losing its grip, some say it’s time to get over the politically correct mentality that prevents profiling. Others search for alternate names to make profiling more palatable.

Alas, there is no profile that can reveal the next terrorist. Judging from recent acts, it could be Saudis, other Middle Easterners, South Asians, West Africans — or Americans. Terrorists are engineers, or students, ne’er-do-wells, U.S. military veterans, or active-duty U.S. military. They have Muslim names, except when their names are Reid, McVeigh or Kaczynski. Attackers invariably enter the country from overseas as tourists, or they are naturalized U.S. citizens, unless they were born in the United States. This confused jumble predicts nothing useful.

“Trusted traveler” plans have similarly flawed security logic. No known biography shows that a person should be treated as a “good guy,” given a biometric ID and accorded lower scrutiny at the airport. What if a “good guy” turns into a “bad guy” after passing the background check?

The alternative that looks best now is risk acceptance. The small risk of domestic undergarment bomb smuggling, suggested by a decade without any such attack, is something the public can tolerate — if prison-style searching of innocent American travelers is the alternative.

This is apostasy in Washington — where the political imperative is zero risk. But risk is a reality of life. We take risks when we drive, when we walk across a street and when we go to the fridge for that two-day-old slice of pizza.

This illusory quest for zero risk helps terrorism achieve its goals. As news of “Operation Hemorrhage” — smaller, low-cost attacks aimed to disrupt commerce and stoke fears — demonstrates clearly, terrorism works by inducing target states to overreact. That’s the only mode terrorists have for affecting major powers like the United States.

We’ve been nothing if not a patsy to their strategy. The element of surprise, central to terrorism, forces us to defend everything against every mode of attack — a logic that naturally bleeds us.

One sure thing is that terrorists might use tactics we have already seen, so the TSA’s first order of business after its creation was to confiscate sharp objects like those used on 9/11. Shoe-bomber Richard Reid produced the policies that expose our socks at TSA checkpoints. The liquid bomb plot gave concessionaires on the far side of the checkpoint a monopoly on bottled water.

So it is that last year’s underwear bomb attack provided the impetus for strip/​grope. No such attack has originated here in a decade, but past performance does not dictate future results — and the TSA’s job is not to find the acceptable risk. Its job is to eliminate risk.

Shoring up support for that policy, and many more, TSA and Department of Homeland Security officials constantly remind us of threats. “Our enemies are observant, patient, stealthy and ruthless,” TSA administrator John Pistole testified before the Senate Commerce Committee last week.

“There is a continued threat against aviation,” said Homeland Security Secretary Janet Napolitano, defending use of strip-search machines, “involving those who seek to smuggle powders and gels that can be used as explosives on airplanes.”

What stands out about these claims is that they can’t be proven false. With no better information to go on, the public has long accepted them. But the public’s discomfort with TSA policies — and these unilateral claims of authority — is growing.

Last week, when the software engineer John Tyner said, “Don’t touch my junk” to a TSA agent about to lay hands on his private parts, Tyner laid down a challenge to the TSA’s new policy, to post‑9/​11 security policy generally and to the authority of threat statements like Pistole’s and Napolitano’s. Don’t tell us there are threats — tell us what the threats are specifically and fully. We’ll decide whether the responses you propose pass muster.

Air travel will never be 100 percent safe. But it would take a lot of successful attacks to make it more dangerous, for example, than driving. If the government were to level with the American people about specific threats — rather than touting threat in the abstract and promising perfect security — the people would likely accept the security procedures that meet the genuine risks.

Ultimately, the federal government’s role should be to develop and disseminate threat information, leaving airlines, airports and the flying public to negotiate among themselves about what the airport experience should be like.

Don’t hold your breath for that to happen soon. But do hold on to your rights, liberties and common sense when you travel this holiday season. They are important parts of the nation’s true counterterrorism arsenal.