The Volstead Act prohibiting intoxicating beverages became law on October 28, 1919—a century ago this week—and came into force a few months later. Most people now agree that Prohibition was a failure, driving the alcohol industry underground, where its products became unsafe, its profits lucrative and tax-free, and its methods violent. Most countries have since taken the view that it is better to legalize, regulate and tax drink than to ban it.

Today, there is a similar debate over vaping, a popular new practice prohibited...