A few weeks ago, as the New York City Council's health committee considered a ban on using electronic cigarettes in public, several fans of the battery-powered devices sat in the audience, demonstrating their operation. "I'm watching puffs of vapor go up in this room," said Councilman Peter Vallone. "It is confusing."

Last week Vallone and 42 of his colleagues demonstrated their confusion by voting to treat vaping like smoking, meaning e-cigarettes will be banned from bars, restaurants, and other indoor spaces open to the public, along with outdoor locations such as parks and beaches. Although that arbitrary edict may relieve the discomfort of politicians bewildered by a new technology, it probably will mean more smoking-related disease and death, the opposite of their avowed goal.

The New York Times called the meeting during which Vallone expressed his dismay at metal tubes that resemble cigarettes "one of the most scientifically vague and emotionally charged health committee hearings in recent memory." New York City Health Commissioner Thomas Farley supplied the scientific vagueness, admitting there is no evidence that e-cigarettes pose a threat to vapers themselves, let alone bystanders. Still, he said, "I certainly can't guarantee that that is safe."

But the real problem with e-cigarettes, according to Farley and other supporters of the ban, is that they look too much like the real thing. "E-cigarettes threaten, in my opinion, to undermine enforcement of the Smoke-Free Air Act," City Council Speaker Christine Quinn said last week. "Because many of the e-cigarettes are designed to look like cigarettes and be used just like them, they can lead to confusion or confrontation."

You might think that people of ordinary intelligence would pretty quickly learn to distinguish a burning stick of dried vegetable matter from an e-cigarette, which contains no tobacco and produces no smoke. And once they learned the difference, they could explain it to the New York City Council. "These are being touted as safer than cigarettes," says Councilman James Gennaro, "but we don't really know that."

Yes, we do. While some questions remain about the long-term effects of inhaling propylene glycol, the government-approved food ingredient that carries nicotine to vapers' lungs, there is no doubt that the hazards of consuming the drug this way pale beside the hazards of consuming it along with the myriad toxins and carcinogens created by tobacco combustion. People who tell you otherwise are blowing smoke—or possibly e-cigarette vapor, since they can't seem to tell the difference.

Smokers can, and those who have switched to e-cigarettes, thereby dramatically reducing the health risks they face, resent being pushed out into the cold again by power-mad politicians wielding frivolous rationales. Gennaro, who co-sponsored the vaping ban, worries that "just seeing people smoking things that look identical to cigarettes in subway cars, colleges and public libraries will tend to re-normalize the act of smoking and send the wrong message to kids."

That scenario seems unlikely, since the main selling point of e-cigarettes is that they eliminate the smelly smoke and dangerous combustion products generated by the regular kind. Nor is there any evidence that vaping is a gateway to smoking: The recent increase in e-cigarette use by teenagers occurred almost entirely among smokers, and it was accompanied by a continued decline in smoking.

Although the literally superficial arguments offered in support of New York's vaping ban are not very persuasive, they reflect the real motivation of people who object to e-cigarettes. They are appalled by this product because it reminds them of tobacco cigarettes, triggering all the emotions of disgust, contempt, and self-righteousness they associate with smoking.

Yet this very same resemblance makes e-cigarettes a promising harm-reduction tool, one that mimics smoking while delivering nicotine in a much cleaner form. Anyone who is truly concerned about the health consequences of smoking should welcome this innovation instead of following New York's example by making it less appealing through gratuitous restrictions that discourage smokers from quitting.