In this issue of AJPH, a distinguished group of tobacco control researchers and practitioners call for a more balanced look at e-cigarettes for reducing the enormous and persistent burden of smoking-caused morbidity and premature mortality-a worthy goal. The article is built around the artifice of a controversy between "fervent opponents" of harm reduction who emphasize risk to young people and "enthusiastic supporters" who want to facilitate smoking cessation and reduce harm with e-cigarettes. This "controversy" exists because we lack evidence on the long-term consequences of policies that promote the use of e-cigarettes for harm reduction, both for the smoking adults who switch to them and for the youths who start using them. Of course, we cannot see or model far enough into the future to have credible projections of the impact of regulatory decisions made now, decisions that will undoubtedly have long-term, generational repercussions.