The issue of environmental tobacco smoke (ETS) and the harms it causes to nonsmoking bystanders has occupied a central place in the rhetoric and strategy of antismoking forces in the United States over the past 3 decades. Beginning in the 1970s, anti-tobacco activists drew on suggestive and incomplete evidence to push for far-reaching prohibitions on smoking in a variety of public settings. Public health professionals and other antismoking activists, although concerned about the potential illness and death that ETS might cause in nonsmokers, also used restrictions on public smoking as a way to erode the social acceptability of cigarettes and thereby reduce smoking prevalence. This strategy was necessitated by the context of American political culture, especially the hostility toward public health interventions that are overtly paternalistic.