A city beset by daunting difficulties could use a scapegoat. So San Francisco politicians must be grateful for Juul Labs, the nicotine-delivery sensation that did them the favor of locating its corporate headquarters at Pier 70. Being closely associated with a recent surge in vaping among teenagers, Juul is an obvious political target on the order of Big Tobacco, but with an irresistible sheen of trendy relevance that cigarettes have long since lost.

Enter City Attorney Dennis Herrera and Supervisor Shamann Walton, who propose no less a sanction for Juul and its ilk than banishment from the city. Their plan, expected to be considered by a Board of Supervisors committee Friday, would take the draconian step of prohibiting e-cigarette sales throughout the city and banning the companies that make them from public property — e.g., the space currently leased by Juul. As Walton put it, “We don’t want them in our city.”

The company, whose flash-drive-like devices have come to dominate a small but rapidly growing sector along with the nightmares of public health advocates, is all contrition these days on the subject of youth vaping. It’s stopped brick-and-mortar retail sales of mango, cucumber and other flavors likely to appeal to minors and made other efforts to discourage underage use. It’s been more defiant of the city, however, pursuing a ballot measure that would supersede a sales ban and, facing the prospect of exclusion from city property, looking to purchase a downtown skyscraper. “We’re stayin’,” chief executive Kevin Burns told our editorial board Thursday.

Burns insists that the company need not spread nicotine addiction among the young or anyone else because it has a worldwide market of a billion smokers in which to grow and fulfill its (possibly newfound) mission of extinguishing the carcinogenic cigarette of yore. The company’s explosive growth has slowed in the wake of its efforts to rein in age-inappropriate vaping, though it remains to be seen whether it can reverse the damage done to declines in nicotine use among the young.

Herrera and Walton’s distaste for and distrust of Juul, of which the tobacco company Altria is a minority owner, is well-founded. But their proposed prohibition would be a blunt and bizarre choice for a city that has largely embraced another drug, marijuana, while seeking to codify its unofficial tolerance of injectable ones. What, no safe vaping sites?

The most absurd result of the measure would be to render electronic nicotine devices illegal while allowing old analog packs of Camels to populate everyone’s favorite corner store.

A total ban of tobacco products would raise familiar enforcement and other questions about prohibition, especially on such a local level, but it would be a more coherent and defensible policy than one that tolerates the most popular and deadly form of nicotine delivery.

While vaping has known and, given its comparative novelty, possibly unknown risks, it is by every expert analysis safer than smoking, the greatest dangers of which come from compounds other than nicotine. To the extent that adult smokers replace cigarettes with vaping, it accomplishes the same goal as safe injection sites: harm reduction.

“It is hard from our position to say why you would leave the most deadly product ever created on the shelf, and that’s OK, and take off a product ... that is a harm reduction product,” Burns said.

The city and the U.S. Food and Drug Administration already have moved to ban flavored nicotine products that are likely to appeal to young people. The supervisors’ energies would be better spent ensuring that Juul and others aren’t promoting addiction among children as they provide adult addicts with less harmful alternatives. That would be truer to the city’s spirit of tolerance and compassion toward a variety of vices and those drawn to them — even if it’s not as satisfying as lighting up a corporate villain.

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