The legal term preemption may have little resonance outside of courts and legislative chambers. But what it describes—the invalidation of state law by federal law, or local law by state law—has profound significance for public health. Preemption affects everything from the quality of medical devices to the extent of tobacco advertising, from the presence of air bags in cars to the disclosure of ingredients in pesticides. In other words, preemption affects just about everything a public health professional does.

But how, and why, is a non-lawyer supposed to understand—much less have anything useful to say about—a concept that even most attorneys do not fully comprehend?

Essentially, the answer is straightforward. Although legal briefs and court opinions about preemption are routinely filled with elaborate and complicated analyses of the issue, outside the courtroom—and particularly inside legislative offices—preemption is mostly a question of policy and political judgment. And policy and politics are extremely relevant to the work of many public health professionals. To participate in those policy discussions and negotiations, non-lawyers need a basic working knowledge of preemption: what it is, how it works, and why its consequences are so important to keep in mind when formulating legislation.

Be sure to checkout NPLAN's preemption fact sheet series.