Today President Donald Trump announced that his administration plans to ban the sale of e-cigarettes in flavors other than tobacco, a move that will undermine public health in the name of promoting it. The ban, which the Food and Drug Administration (FDA) will impose through regulatory "guidance" it plans to issue soon, will dramatically reduce the harm-reducing alternatives available to smokers who are interested in quitting and is likely to drive many people who have already made that switch back to a much more dangerous source of nicotine.

The flavor ban is aimed at preventing underage vaping, which increased sharply last year. "We are going to have to do something about it," Trump told reporters, describing vaping by teenagers as "a new problem in the country."

Yet in terms of numbers and health consequences, the main impact of the ban will be felt by the millions of adults who have used e-cigarettes to quit smoking. Those adult vapers overwhelmingly prefer the flavors that the FDA plans to ban, and many of them, deprived of the products they are now using, are apt to start smoking again, dramatically increasing the health risks they face. The upshot will be more smoking-related disease and death.

Since selling e-cigarettes to minors is already illegal, a more reasonable approach would have been to improve enforcement of age restrictions. Companies such as Juul, the leading e-cigarette maker, have already taken steps in that direction through robust age verification. If some retailers are still selling e-cigarettes to minors, a logical response would have been to crack down on them. Instead the Trump administration is depriving adults of potentially lifesaving products that seem to be nearly twice as effective in facilitating smoking cessation as alternatives such as nicotine gum and patches.

Trump seems to have been influenced by his wife, Melania, who recently tweeted that "we need to do all we can to protect the public from tobacco-related disease and death, and prevent e-cigarettes from becoming an on-ramp to nicotine addiction for a generation of youth." Yet the flavor ban will undermine that first goal by eliminating the vast majority of the vaping products that provide nicotine without tobacco or combustion. Since the availability of e-cigarettes seems to have accelerated the long-term decline in smoking, the flavor ban can be expected to slow that trend or even reverse it.

The FDA has repeatedly acknowledged the enormous harm-reducing potential of e-cigarettes. Former FDA Commissioner Scott Gottlieb openly agonized about the tradeoff between broad restrictions aimed at preventing underage consumption and the interests of smokers who want to quit or have already done so with the help of e-cigarettes. This decision gives no weight to those interests. The only consolation is that Trump's announcement takes the shine off Michael Bloomberg's latest crusade.