But federal preemption jumped sharply in the 1970s and again over the past decade. About 6 percent of federal laws enacted between 2000 and 2009 preempt state and local powers, compared with about 3.5 percent during the previous decade.
To learn more about how the parties at the national level approach states’ rights, we surveyed every federal law enacted between 1990 and 2012 that preempted state power in some way. As the figure below shows, we found that both parties have contributed relatively equally to the dramatic increase in federal preemption.
The parties enact different types of preemptions. Republicans are more likely to impose what are known as “ceiling preemptions.” These laws cap the amount of regulation states can enact on a particular issue. For example, a ceiling preemption might prohibit states from setting new or more stringent emissions standards for a particular industry.
Democrats, by contrast, are much more likely to limit state power by setting floor preemptions, or minimum standards that states must meet but can exceed if they want to. For example, such a law might set a federal emission standard for a particular industry but allow states to enact tougher emissions standards.