Public-health policy — especially regarding children — is being driven by the Voltaire Rule: The perfect is the enemy of the good.

Take the current mania about vaping and, most recently, a product called Juul. News reports are replete with high-school officials fretting about how hard it is to monitor the product because it looks like a flash drive and doesn’t produce the same smoke as traditional cigarettes.

Indeed, a Juul — which electronically heats nicotine into a vapor — can be recharged through a computer’s USB port. Juul pods are also flavored — fruit medley and cool mint are two examples — so the smell isn’t the same as combustible tobacco products.

In February and March a trickle of reports about the danger to teens from vaping turned into a tsunami of press about the supposed “epidemic” of youth Juuling. That flood turned into a howl from public health officials and legislators on Capitol Hill that the FDA should do something about this terrible threat to children.

In turn, FDA Commissioner Scott Gottleib announced last week the agency would investigate what Juul and two other vaping manufacturers were doing to prevent young people from getting their hands on these products. Gottleib is especially concerned about “why kids are finding these products so appealing” so that the agency can “address it.”

Juul Labs has also responded to the outcry by ponying up a whopping $30 million to make sure kids don’t get their hands on their product. The company said it would work with state and local authorities to raise the minimum age for tobacco and vaping products to 21.

And this nine months after the San Francisco-based firm voluntarily raised the minimum age for purchasing Juul from its Web site to 21. (Juul Labs, which is responsible for half of all e-cigarette sales in the US, can probably afford it.)

The odd part is that whereas vaping products are gaining popularity among adults, cigarette use and vaping among young people are falling. According to the Centers for Disease Control and Prevention, the percentage of high-school students who smoke cigarettes dropped from 22 percent to 14 percent between 2011 and 2016. And for e-cigarettes, high school users dropped from 16 percent to 11 percent from 2015 to 2016.

The whole idea behind vaping in general and Juul in particular is to move traditional smokers to e-cigarettes, which according to England’s national health agency would mean healthier adults since vaping products do not contain the same dangers as traditional cigarettes. But instead of aiming for good outcomes, prohibitionists want only a perfect ban.

They’ve been at this for a while. As former New York Times science reporter John Tierney wrote for City Journal last year, Obama administration appointees at the CDC and surgeon general’s office led the effort to cover up “data showing vaping’s benefits and using their funding powers to pressure local health officials to ban the practice.”

The FDA had “forbidden e-cigarette firms from mentioning any health advantages over cigarettes,” as well as “adopting rules to outlaw virtually all existing vaping devices” by 2018. When the Trump administration took over, the FDA announced that the agency was going to delay a decision on vaping products until 2022.

Since the election, the American Cancer Society and American Academy of Pediatrics, as well as public-health-advocacy groups like Campaign for Tobacco-Free Kids and Truth Initiative, have been hammering the regulators.

At nearly the same time the anti-Juul stories started appearing in the media, the same anti-tobacco groups and public-health professionals went to court in Maryland to sue the FDA over vaping regulations, demanding it return to its Obama-era position against vaping and regulate these products out of existence.

Vaping is better than cigarette smoking and nationally high schoolers aren’t doing much of either, but extremist activists are screaming and yelling about a vaping epidemic among young people that doesn’t seem to exist. Prohibitionists are provoking hysteria instead of commonsense regulation.

Abby W. Schachter is the author of “No Child Left Alone: Getting the Government Out of parenting.”