Twenty years ago this month, I joined 45 other state attorneys general to enter into the landmark settlement with the tobacco industry. Since then, the U.S. cigarette smoking rate fell from 24 percent of adults to 14 percent last year — the lowest ever.

We have the opportunity to go much lower. But we’re also at risk of reversing these gains if we fail to give smokers safe alternatives to cigarettes.

E-cigarettes are prompting a great deal of discussion and debate, especially regarding their use by children. [...]