For this study, preemptive legislation was defined as legislation that prevents any local jurisdiction from enacting restrictions that are more stringent than the state law or restrictions that may vary from the state law. Data included the preemptive provisions of these laws. A multistep process was used to identify the month and year the preemptive provisions of these laws took effect. The process included identifying the history of the law by finding the records of each state's legislative session in a given year and analyzing the session laws to determine the effective date of the law's provision.
Some preemptive provisions are very narrow.
For example, in New York, the state government has precedence over local government restrictions on the free distribution of samples of tobacco products. Other provisions are broad. For example, in Tennessee, minors' access laws preempt local legislation of all tobacco-control areas. The results of a linear regression analyzing the number of preemptive provisions per law and the years they became effective indicated a significant increase in the number of provisions from 1993 through 1996. During the 1980s, nine states passed 11 preemptive laws covering 21 provisions.