A 29-story office building at 123 Mission St. in San Francisco illustrates the policy puzzles that fester because of these facts: For centuries, tobacco has been a widely used legal consumer good that does serious and often lethal harm when used as it is intended to be used. And its harmfulness has been a well-established and widely publicized scientific proposition for generations.

The building is the headquarters of Juul, a large company that markets vaping products ¡ª electronic cigarettes ¡ª that has been running full-page ads in major newspapers ostensibly attempting to limit sales of its product: ¡°Youth vaping is a serious problem¡± that justifies ¡°cracking down on underage sales at retail stores¡± and removing from stores ¡°flavored products.¡± Juul¡¯s flavors include mint, mango, fruit and cucumber. Other companies¡¯ flavors have included ¡°Unicorn Puke¡± and ¡°Zombie Juice.¡± The target audience is not mature.

This city, Juul¡¯s host, recently banned such products from being sold in stores or online and delivered to city addresses. Its purpose is to limit cigarette smoking, the nation¡¯s foremost cause of preventable death. Well.