Just as television coverage of breaking news can “preempt” the programs that would otherwise be airing, so too valid federal statutes can preempt state law that would otherwise apply. That is a consequence of the Supremacy Clause, which makes valid federal statutes part of “the supreme Law of the Land” and says that “the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.” But exactly what does it mean to say that federal statutes are “supreme” over state law? Under what circumstances does the Supremacy Clause require judges to disregard otherwise applicable state law because it is contrary to federal law?
The Supremacy Clause definitely does not mean that each state must base all of its own laws on the same policy judgments reflected in federal statutes. For instance, the fact that Congress has chosen to establish federal income taxes, but has mostly refrained from establishing federal sales taxes, does not mean that state legislatures have to make the same choice as a matter of state law. Of course, states cannot exempt people from having to pay federal income taxes as required by federal law. But states do not have to structure their own state tax systems on the same model; if state lawmakers think that sales taxes are better than income taxes, states can fund their state governments that way. Similarly, the fact that Congress has made the possession of certain drugs a federal crime does not prevent states from following a different policy as a matter of state law. While states are not in charge of whether drug possession is a federal crime, they are in charge of whether it is also a state crime.
In these examples, though, the relevant state law does not interfere with the operation of the federal statute. Federal authorities can enforce the federal income tax or federal drug laws without regard to whether state law imposes a state income tax or criminalizes possession of the same drugs.
When application of state law would interfere with the operation of a valid federal statute, modern courts are more likely to conclude that the state law is preempted. Ever since Hines v. Davidowitz (1941), the Supreme Court has sometimes articulated a broad version of this idea. The majority opinion in Hines arguably suggested that state law is preempted whenever its application “stands as an obstacle to the accomplishment and execution of the full purposes and objectives” behind a valid federal statute, and later cases have repeated this formulation.
I do not think that the Supremacy Clause itself compels this understanding of the preemptive effect of federal statutes. In my view, the fact that valid federal statutes are “the supreme Law of the Land” and “the Judges in every State shall be bound thereby” means that the judges in every state must follow all legal directives validly supplied by those statutes. In any case where following some aspect of state law would require disregarding a legal directive validly supplied by a federal statute, judges should conclude that the state law is preempted; if judges have to choose between applying state law and applying a legal directive validly supplied by a federal statute, the Supremacy Clause gives priority to the federal law. But unless state law contradicts federal law in this sense (so that judges must choose which one to follow), nothing in the Supremacy Clause prevents judges from following both.
When the Supremacy Clause was adopted, judges had long been using an analogous test to decide whether one law repeals another. Ordinarily, statutes enacted by the same legislative body are cumulative: if a legislature enacts two statutes at different times, and if Statute #2 does not say that it repeals Statute #1, courts normally will apply both. But that is not possible if the two statutes supply contradictory instructions for the same issue. With respect to statutes enacted by a single legislature, courts traditionally have handled such contradictions by giving priority to the more recent statute. With respect to conflicts between state and federal law, the Supremacy Clause establishes a different hierarchy: federal law wins regardless of the order of enactment. But this hierarchy matters only if the two laws do indeed contradict each other, such that applying one would require disregarding the other. In my view, then, the trigger for preemption under the Supremacy Clause is identical to the traditional trigger for repeals. In support of this conclusion, there is evidence that the Supremacy Clause was drafted and discussed in light of existing legal doctrines about repeals.
Even if I am right about the Supremacy Clause’s test for preemption, though, applying that test in particular cases requires courts to interpret the relevant federal statutes to identify all the legal directives that those statutes establish. That is a more contentious project than nonlawyers might assume. Federal statutes often are understood to imply some things that they do not say on their face, and legal directives that are established by implication can be just as valid as other legal directives. Different judges, however, have different views about the circumstances in which courts can properly read things into federal statutes (and, perhaps, about the extent to which courts can properly articulate subsidiary rules designed to help implement those statutes). The competing schools of thought include one approach called “textualism” and another called “purposivism.”
The Supreme Court issued its opinion in Hines during the heyday of purposivism, and there is reason to think that Hines’s emphasis on Congress’s “purposes and objectives” was more about statutory interpretation than about the basic test for preemption established by the Supremacy Clause. In keeping with that idea, the modern Supreme Court tends to portray the Hines formulation as a guide to the “pre-emptive intent” that courts should attribute to particular federal statutes. On this way of thinking, the Hines formulation reflects a presumption about Congress’s likely desires. The idea is that when Congress enacts a federal statute, Congress presumably wants to preempt state laws that would “stand as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress,” and courts should give effect to this presumed intention.
If, as a matter of statutory interpretation, a particular federal statute implicitly forbids states to enact or enforce laws that would interfere with specified federal purposes, and if Congress has the constitutional power to impose this restriction on state law, then the Supremacy Clause would require courts to pay attention. After all, if a federal statute validly strips states of the power to enact or enforce certain kinds of laws, a court that gave effect to such a state law would be disregarding a valid federal directive, in violation of the Supremacy Clause. Considered as a principle of statutory interpretation, then, the Hines formulation can co-exist with my understanding of the Supremacy Clause.
Still, the Hines formulation may not be a very good principle of statutory interpretation. To begin with, many textualists doubt that courts are in a good position to identify the full purposes and objectives behind any particular federal statute. In any event, members of Congress would not necessarily want to run roughshod over all state laws that serve competing goals. To take a simple example, a federal statute that exempts multinational companies from certain federal taxes might have the purpose of luring business to the United States, but courts should not automatically infer that Congress is forbidding states to enforce their own generally applicable tax laws against such companies. Likewise, a federal statute that gets rid of prior federal regulations in a particular area might be designed to reap the benefits of the free market, but courts should not automatically infer that Congress must have wanted to prevent individual states from enacting any regulations of their own in the same area.
In the past few decades, the Supreme Court has become somewhat more sensitive to these points. As early as 1992, Justice Kennedy wrote that “[o]ur decisions establish that a high threshold must be met if a state law is to be pre-empted for conflicting with the purposes of a federal Act.” More recently, Chief Justice Roberts has quoted this statement approvingly, and Justices Alito and Sotomayor have both quoted Chief Justice Roberts’s quotation. Meanwhile, Justice Thomas has rejected the Hines formulation entirely.
At the very least, the Supremacy Clause does not itself require judges to conduct the analysis described in Hines and its progeny. In my view, that analysis is appropriate only to the extent that individual federal statutes are properly interpreted to call for it.
Some of the arguments presented here initially appeared in Preemption, 86 Virginia Law Review 225 (2000).
Caleb Nelson Emerson G. Spies Distinguished Professor of Law, University of Virginia School of Law