According to a recent nationwide survey of registered voters by Zogby International, 45% of Americans said yes. Among 18-29 year olds, 57% were in favor.

Maybe it's time to ask: what if cigarettes became the new Prohibition?

The upside is clear. Millions of American smokers would finally quit, and millions more would never start. Smoking-related death and disease would drop significantly. That's all to...