A broad consensus exists among public health practitioners and tobacco control advocates that preemption has an adverse impact on tobacco control efforts [4, 5]. The Healthy People 2020 Tobacco-Use Objective TU HP2020-16 seeks the elimination of state laws that preempt stronger local tobacco control laws [6]. Preemptive state laws prevent local governments from taking action to protect residents from the well-documented dangers of tobacco use and secondhand smoke exposure [7]. This is a significant loss, as the strongest and most innovative smoking restrictions—and tobacco control policies in general—have traditionally emerged first at the local level before ultimately being adopted at the state level [8, 9]. The tobacco industry's difficulty in influencing local policy making and the greater influence it is typically able to exercise at the state level have led the industry to lobby forcefully for preemption of smoke-free laws [10–15]. In internal documents, the tobacco industry has expressed concern that strong smoke-free laws will lead to reduced social acceptability of smoking and decreased cigarette sales, while in public the industry has argued, usually indirectly through third-party organizations, that preemption is necessary to ensure a “level playing field” among businesses in different communities, to preserve business proprietors' ability to set their own smoking policies and to prevent local smoke-free laws from adversely impacting restaurant and bar business [8, 13]. In fact, preemptive legislation has often appeared to be a direct response to local smoke-free policy progress. The tobacco industry and its allies have often introduced such legislation shortly after the adoption or consideration of the first local smoke-free ordinances in a state [8, 13].

Successful efforts to impede the adoption of local smoke-free laws have the potential for repercussions beyond reduced protections for nonsmokers. Research, including some conducted by the tobacco industry, has demonstrated that smoke-free policies can also contribute to increased quit attempts and increased success in quitting among adult smokers as well as reduced cigarette consumption among smokers who continue to smoke [13, 16–19]. Tobacco control practitioners believe that preemptive laws have other negative effects, including loss of opportunities for the public debate and education that typically accompany consideration of local smoke-free laws, less vigorous local enforcement efforts, and lower levels of compliance [8, 14, 20–22]. The number of state laws preempting stronger local smoking restrictions increased sharply in the 1990s [14, 15]. In many states, provisions preempting local smoking restrictions were coupled with weak statewide smoking restrictions that contained many exemptions. While some states' preemptive provisions applied only to certain settings (e.g., restaurants in Michigan), allowed local policy making in a limited number of local jurisdictions (e.g., Illinois), or grandfathered local ordinances enacted before a certain date (e.g., Oregon), most states' preemptive provisions were comprehensive in scope, applying to all settings and all local jurisdictions in the state, and effectively blocking any local action in this regard [14].

After peaking in the mid-1990s, the pace of adoption of new state measures preempting local tobacco control policy making leveled off after 1996 [14]. As the pitfalls of preemption became apparent, advocates have pushed for inclusion of explicit non-preemption clauses in state-legislation restricting smoking [1, 20]. In 2002, Delaware became the first state to successfully repeal a provision preempting local smoking restrictions, and eight other states—Illinois, Louisiana, Mississippi, Nevada, New Jersey, Oregon, Iowa, and North Carolina (which rescinded its preemption provisions for some settings, but not for others)—have followed suit, either in conjunction with adoption of a statewide smoke-free law or as a stand-alone action [23]. In other states, such as Kentucky [24] and South Carolina [25] state courts have ruled that state statutes—once widely thought to be preemptive—do not prohibit passage of local smoke-free laws [26]. Although progress is clearly being made toward achieving the Healthy People 2020 goal of no preemptive state smoke-free laws, as of December 31, 2011, 12 states are still considered to preempt local smoking restrictions in at least one of three major settings (government workplaces, private workplaces, or restaurants) [27].

A comprehensive literature review found just one published study to date that has sought to quantify the impact of state laws preempting local smoking restrictions. Stark and colleagues examined the effect of an Oregon law which preempted local smoking restrictions in conjunction with the establishment of partial statewide smoking restrictions. The law grandfathered in existing local ordinances that were stronger than the state standard. The authors found that nonsmoking restaurant and bar employees working in the preempted communities had elevated levels of a tobacco-specific carcinogen compared to their counterparts working in the grandfathered communities [28].

The most striking finding of the study is that state preemptive laws are associated with reduced support for smoke-free environments in indoor settings among current smokers. (A similar effect was found among former and never smokers, but it was not significant.) In other words, current smokers in states with preemption were less likely to express support for smoke-free environments than their counterparts in states without preemption. State preemption could have this effect by preventing or delaying shifts in social norms that may be generated in part by the discussion, adoption, and implementation of local smoke-free laws.

The discussion and debate that typically occur when communities are considering adopting smoke-free ordinances may raise public awareness regarding the health effects of secondhand smoke and the need for smoke-free policies and contribute to changes in public attitudes regarding the social acceptability of smoking [8, 13]. This discussion also generates news media coverage [32, 33]. Studies have suggested that increased news media coverage of tobacco issues, in turn, is associated with decreases in annual per capita cigarette consumption, decreases in weekly cigarette sales, and increases in adult tobacco use cessation [32, 34–36]. Increased news coverage of secondhand smoke issues may also be associated with increased adoption of local smoke-free laws [37].

In addition to losing opportunities for discussion, residents in preemption states also lose the opportunity to live under smoke-free ordinances. This is a significant loss, as a number of studies have reported that public support for smoke-free environments increases after smoke-free laws go into effect [18, 38, 39]. Studies have found that this effect is especially pronounced among smokers, in part because their baseline levels of support are typically lower than those of nonsmokers [18, 39, 40]. It may be that having the experience of actually living under a smoke-free law dispels concerns about potential adverse effects of such laws and provides firsthand evidence of their benefits. It may also be that people, and smokers in particular, simply adjust to and become accustomed to these laws.

Evidence from a number of states' experiences suggests that the shifts in social norms that occur when smoke-free laws are being considered, adopted, and implemented foster a climate that supports smoking cessation, reduced adult tobacco use, and reduced youth tobacco use initiation [13, 17–19, 41–43]. Evidence also indicates that these shifts lead to increased efforts to reduce secondhand smoke exposure even in settings which are not covered by smoke-free laws, for example, increased adoption of voluntary smoke-free home rules [18, 39]. In fact, the evidence indicates that such changes in public attitudes, which are largely generated by smoke-free laws and other tobacco control policies, are one of the single most important mechanisms through which state and local tobacco control programs reduce tobacco use [44–46]. One of the most significant, although indirect, effects of state preemptive laws may be their denial to state residents of the opportunity to have these experiences during the discussion, adoption, and implementation of smoke-free ordinances, and to undergo the resulting shifts in social norms. This may perpetuate disparities among states in tobacco control policies and tobacco use by freezing local policies and norms in place, thus impeding the efforts of these states to “catch up” with states that have achieved greater progress in reducing tobacco use.

The study also demonstrates that state preemptive provisions are associated with a reduced level of worker protection from secondhand smoke. Indoor workers in states with preemption provisions are less likely to be covered by smoke-free workplace policies than their counterparts in states without preemption.

The implementation of smoke-free laws and smoke-free workplace policies is associated with increased cessation among adult smokers and reduced adult smoking prevalence [13, 17–19]. Several studies have suggested that smoke-free laws and policies are also associated with reduced youth smoking initiation [41, 42]. These effects could operate through several mechanisms, including reduced opportunities to smoke, reduced cues prompting smoking, and shifts in public attitudes regarding the social acceptability of smoking.

This analysis also suggests that state preemptive provisions are associated with fewer local ordinances restricting smoking. This is in keeping with the findings of previous reviews [7, 8, 13].

It should be noted that there are some exceptions to this finding. Some states with preemption have local ordinances in place. This can be due to a number of factors. For example, North Carolina provided a window of opportunity for local jurisdictions to adopt ordinances restricting smoking before the state preemption provision took effect. Other states, such as Illinois, preserved local control in some communities which had already adopted local smoking restrictions before the preemptive state law took effect (i.e., these communities could revisit and strengthen their ordinances). Some states, such as Michigan, preempt local smoking restrictions only in certain venues, while allowing such restrictions in other venues. In other states, such as Florida, local smoking restrictions adopted before the preemptive state law remain in the books, but are not enforced. And in some states local jurisdictions may have passed smoking restrictions, unaware of potential impediments to such action posed by state statutes and legal precedents. However, the data bear out the common sense proposition that the absence of preemption is in most cases a necessary, though not sufficient, condition for the adoption of local smoking restrictions.

This study has some noteworthy strengths, including nationally representative data and control for a variety of state policy and individual-level variables. The study is also subject to several limitations. In particular, because the study is cross-sectional and examines the relationship between state preemption laws and the three outcomes of interest at a single point in time, it cannot establish the causality of the observed associations.

Opponents of smoke-free legislation have not abandoned the use of preemption to impede the adoption of comprehensive local smoking restrictions. In recent years, tobacco control advocates have noted instances in several states of legislation that carves out exemptions for specific venues (e.g., cigar bars and outdoor seating in restaurants) while preempting local governments from restricting smoking in these venues.

In conclusion, this study suggests that state provisions preempting local smoking restrictions affect several outcomes in ways that could impede progress in advancing secondhand smoke protections and broader tobacco control efforts. The issue of the implications of preemption is not unique to tobacco control. Preemption of stronger restrictions at lower jurisdictional levels has surfaced with regard to a number of other public health issues, including alcohol control, and, most recently, menu labeling requirements for restaurants. Because it is somewhat a technical issue and can initially appear to be innocuous, preemption can easily be overlooked, but it can have profound implications. It took tobacco control practitioners and advocates several years to reach consensus on the dangers of preemption—years during which several additional states enacted preemptive laws. It is important that practitioners and advocates working on other public health issues fully understand the benefits of local policymaking and the potential impact of preemption.