San Francisco voters are heading to the polls on Tuesday to decide whether theirs will be the first city in the nation to ban all flavored tobacco products. If passed, Proposition E will prohibit not just the sale of menthol cigarettes and flavored cigars but also flavored e-cigarette products.

Prohibition always presents problems but what makes Prop E unique is that it intends not just to ban lethal categories of tobacco products but products that actually help people quit smoking.