Article VI, Clause 2 — Supremacy Clause

ArtVI.C2.1 Overview of Supremacy Clause

The Supremacy Clause was a response to problems with the Articles of Confederation (the Articles), which governed the United States from 1781 to 1789. The Articles conspicuously lacked any similar provision declaring federal law to be superior to state law. As a result, during the Confederation era, federal statutes did not bind state courts in the absence of state legislation implementing them. To address this issue and related political difficulties, the Confederation Congress called for a convention in 1787 to revise the Articles. While the Supremacy Clause was not a source of major disagreement at the Constitutional Convention that followed, it generated intense controversy during debates over the Constitution’s ratification. But advocates of federal supremacy prevailed. The Constitution was ratified in 1788 with the Supremacy Clause.¹

The Supremacy Clause is among the Constitution’s most significant structural provisions. In the late eighteenth and early nineteenth centuries, the Supreme Court relied on the Clause to establish a robust role for the federal government in managing the nation’s affairs. In its early cases, the Court invoked the Clause to conclude that federal treaties and statutes superseded inconsistent state laws. These decisions enabled the young Republic to enforce the treaty ending the Revolutionary War, charter a central bank, and enact other legislation without interference from recalcitrant states.²

The Supreme Court continued to apply this foundational principle—that federal law prevailed over conflicting state law—throughout the latter half of the nineteenth century.³ But other aspects of the Court’s federalism jurisprudence limited the Supremacy Clause’s role during that era. Throughout this period, the Court embraced what academics have called the doctrine of “dual federalism,” under which the federal government and the states occupied largely distinct, non-overlapping zones of constitutional authority.⁴ While federal supremacy persisted as a background principle during these years, the Court’s bifurcation of federal and state authority minimized the instances in which the two could conflict.⁵

To the extent that the Supremacy Clause did play an explicit role in the federalism disputes of this era, the Supreme Court applied it in ways that reinforced dual federalism’s sharp division of federal and state power. In a series of early-twentieth-century decisions, the Court developed a precursor to the doctrine of “field preemption”—the principle that some federal legislation implicitly prevents states from adopting any laws regulating the same general subject. Some of the Court’s early field-preemption decisions aggressively employed the new doctrine, concluding that any congressional action in certain fields automatically displaced all state laws in those fields.⁶

But the Supreme Court’s initial foray into field preemption soon gave way to broader legal and political trends. During the New Deal era of the 1930s and 1940s, the Court acceded to demands for a more active national government by revising other elements of its federalism jurisprudence.⁷ This about-face marked the demise of dual federalism, as the Court expanded the areas in which the federal government and the states possessed concurrent authority. To prevent the federal government’s newly expanded powers from smothering state regulatory authority, the Court simultaneously narrowed the circumstances in which federal law displaced state law. Besides retreating from the “automatic” field preemption of the early twentieth century, the Court articulated a “presumption against preemption,” under which federal law does not displace state law “unless that was the clear and manifest purpose of Congress.”⁸

As the preceding discussion suggests, the Supreme Court has channeled contemporary Supremacy Clause doctrine into the language of “federal preemption.” The Court’s cases recognize several types of preemption. At the highest level of generality, federal law can preempt state law either expressly or impliedly. Federal law expressly preempts state law when it contains explicit language to that effect.⁹ By contrast, federal law impliedly preempts state law when that intent is implicit in its structure and purpose.¹⁰

The Court has also identified different subcategories of implied preemption. As noted, field preemption occurs where federal law is “so pervasive as to make reasonable the inference that Congress left no room for the States to supplement it,” or where “the federal interest is so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject.”¹¹ In contrast, conflict preemption occurs where compliance with both federal and state law is impossible (“impossibility preemption”) or where state law poses an obstacle to federal objectives (“obstacle preemption”).¹²

Because preemption issues are primarily questions of statutory interpretation, the Supremacy Clause’s role in contemporary legal doctrine differs from that of many other constitutional provisions. The basic principle enshrined in the Clause—federal supremacy—is now well-settled. Generally, litigants do not dispute the Clause’s meaning or advance conflicting theories on its scope. Rather, preemption cases ordinarily turn on the same types of issues—like the textualist/purposivist divide and administrative deference—that recur in all manner of statutory litigation.¹³

This essay chronicles the Supremacy Clause’s evolution from a deeply controversial repudiation of the Articles of Confederation to its contemporary role as an essential bedrock of the structural Constitution.

ArtVI.C2.2.1 Articles of Confederation and Supremacy of Federal Law

The Supremacy Clause was a response to the political regime established under the Articles of Confederation (the Articles), which governed the United States from 1781 to 1789.¹ The Articles established a weak national government, providing that the states retained their “sovereignty, freedom, and independence, and every Power, Jurisdiction, and right” that was not “expressly delegated to the United States, in Congress assembled.”² Under the Articles, the Confederation Congress—which performed both legislative and executive functions—had the power to wage war, coin money, establish post offices, and negotiate with Indian tribes.³ But the Confederation Congress could not levy taxes or regulate interstate commerce. Moreover, the Articles did not make federal law supreme over state law. While Article XIII required states to “abide by the determinations of” the Confederation Congress,⁴ the effect of that provision was limited. Indeed, under Article XIII, it was unclear whether federal law was binding in state courts without state legislation implementing it.⁵ James Madison thus criticized the Articles as establishing “nothing more than a mere treaty” of “amity of commerce” and “alliance” in which federal law was merely “recommendatory” for the states.⁶

Article XIII’s ambiguity on federal supremacy was particularly important vis-à-vis the Treaty of Paris, which ended the Revolutionary War between Britain and the United States in 1783.⁷ Among other things, the treaty prohibited “impediment[s]” to the recovery of pre-war debts.⁸ But the lack of clarity over federal supremacy—coupled with an absence of state legislation implementing the treaty—created uncertainties surrounding the enforcement of state laws impairing the rights of British creditors.⁹ These types of uncertainties—and broader dissatisfaction with the national government’s weakness—prompted the Confederation Congress to call for a convention in 1787 to “revis[e]” the Articles.¹⁰

ArtVI.C2.2.2 Supremacy Clause and the Constitutional Convention

Despite the Constitutional Convention’s limited mandate, its delegates began drafting an entirely new constitution shortly after convening. During the drafting process, the delegates considered several options for resolving conflicts between federal and state law. One proposal—the Virginia Plan—would have granted Congress the power to veto state laws and employ military force against states that disobeyed federal law.¹ Another option—the New Jersey Plan—also proposed giving Congress the power to use military force against recalcitrant states, and included a provision that one scholar has described as the “incubus” of what became the Supremacy Clause.² This provision read:

Resd. that all Acts of the U. States in Congs. made by virtue & in pursuance of the

powers hereby & by the articles of confederation vested in them, and all Treaties made

& ratified under the authority of the U. States shall be the supreme law of the

respective States so far forth as those Acts or Treaties shall relate to the said States or

their Citizens, and that the Judiciary of the several States shall be bound thereby in

their decisions, any thing in the respective laws of the Individual States to the contrary

notwithstanding. . . .³

While the Convention ultimately rejected the New Jersey Plan and proceeded with consideration of the Virginia Plan, it dispensed with the latter’s proposals for a congressional veto and the use of military force. Instead, the Convention unanimously approved a provision that closely tracked the New Jersey Plan’s “supremacy clause.”⁴

In July 1787, the Convention adjourned to allow the Committee of Detail to draw up a draft constitution.⁵ The Committee of Detail’s final report contained a “supremacy clause” that read:

The Acts of the Legislature of the United States made in pursuance of this

Constitution, and all treaties made under the authority of the United States shall be

the supreme law of the several States, and of their citizens and inhabitants; and the

judges in the several States shall be bound thereby in their decisions; anything in the

Constitutions or laws of the several States to the contrary notwithstanding.⁶

This provision departed from the clause approved by the Convention as a whole by explicitly providing that federal law was supreme over state “Constitutions,” in addition to state “laws.”

When the Convention considered the Committee of Detail’s report, it unanimously approved an amendment clarifying that the federal Constitution itself—in addition to federal statutes and treaties—was supreme over state law.⁷ The Convention’s Committee of Style ultimately placed the Supremacy Clause in Article VI, immediately before a provision requiring all judges to take an oath supporting the Constitution.⁸ The final Supremacy Clause read:

“This Constitution, and the Laws of the United States which shall be made in

Pursuance thereof; and all Treaties made, or which shall be made, under the Authority

of the United States, shall be the supreme Law of the Land; and the Judges in every

State shall be bound thereby, any Thing in the Constitution or Laws of any State to the

Contrary notwithstanding.”⁹

ArtVI.C2.2.3 Debate and Ratification of Supremacy Clause

The Supremacy Clause generated significant controversy during debates over the Constitution’s ratification. Anti-Federalist opponents of the Constitution argued that the Clause would make the national government overly powerful and infringe on state sovereignty. The stridency of these criticisms varied.

One Anti-Federalist contended that the Clause would force the country into “one large system of lordly government.”¹ Another critic similarly argued that the Constitution would effectuate “a complete consolidation of all of the states into one, however diverse the parts of it may be.”² Some Anti-Federalists framed this criticism as a conceptual argument, asserting that two sovereigns could not exist within the same territory, and that one would “necessarily” destroy the other.³ Along these lines, one opponent claimed that the Supremacy Clause would allow the federal government to prevent states from levying taxes and thereby “absorb” their powers.⁴

Other Anti-Federalists offered more limited criticisms. Some critics objected to making treaties supreme to state law. These commentators contended that this aspect of the Supremacy Clause would allow for the displacement of state law without the approval of both Houses of Congress, because the President and the Senate could make treaties without the approval of the House of Representatives.⁵ Some opponents also argued that, without a federal bill of rights, the Supremacy Clause would allow the federal government to override state constitutional guarantees of individual liberties.⁶

Federalist supporters of the Constitution rejected these arguments. Some supporters dismissed concerns about the elimination of state governments, noting that the Constitution granted the federal government only limited powers.⁷ Others minimized the Supremacy Clause’s significance, characterizing it as a truism that “resulted by necessary and unavoidable implication from the very act of constituting a Federal Government[ ] and vesting it with certain specified powers.”⁸ In response to concerns about the treaty power, Federalists contended that the supremacy of treaties was essential to the federal government’s credibility as a negotiator with foreign powers.⁹ Others argued that, while the House of Representatives had no formal role in the ratification of treaties, it nevertheless operated as a “restraining influence” on that process because of its general legislative powers.¹⁰ Finally, while a federal Bill of Rights was ultimately adopted after the Constitution’s ratification, some Federalists challenged the necessity of those amendments during the ratification debates.¹¹ These advocates contended that explicit rights guarantees were superfluous, because the federal government’s limited powers would prevent it from infringing individual liberties.¹²

The Federalists prevailed. In June 1788, New Hampshire became the ninth state to ratify the Constitution, giving it effect in the ratifying states.¹³ Federal law thus became the “supreme Law of the Land.”¹⁴

ArtVI.C2.3.1 Early Doctrine on Supremacy Clause

The balance of power between the federal government and the states continued to be a source of controversy after the Constitution’s ratification.¹ But in a series of foundational decisions, the Supreme Court interpreted the Supremacy Clause as establishing a robust role for the national government in managing the nation’s affairs. In 1796, the Court held that the Treaty of Paris—which, as noted, prohibited impediments to the recovery of pre-war debts—superseded a Virginia statute allowing debtors to satisfy any obligations to British subjects by payment to the state treasury.²

Slightly more than two decades later, the Court again invoked the Supremacy Clause to resolve another hotly contested political dispute. In 1819, the Court held in McCulloch v. Maryland that a state tax on notes issued by the Second Bank of the United States impermissibly conflicted with federal law.³ The Bank had attracted criticism from skeptics of federal power, who challenged Congress’s authority to charter it. In McCulloch, the Court sustained the federal government’s power to charter the Bank under the Necessary and Proper Clause, while invalidating the state tax on the Bank’s notes under the Supremacy Clause. Writing for the Court, Chief Justice John Marshall explained that “the power to tax involves the power to destroy,” striking down the state tax because it unlawfully burdened the Bank’s operations.⁴

Five years after McCulloch, the Court employed similar reasoning in Gibbons v. Ogden, holding that federal coastal licenses displaced a state law conferring a monopoly on a steamboat company.⁵ After concluding that Congress had the authority to issue the licenses under the Commerce Clause, Chief Justice John Marshall explained that the licenses superseded the relevant state law, which “interfere[d] with” federal policy.⁶ The early Court thus gave shape to the basic principle underlying the Supremacy Clause: where federal and state law clashed, federal law was supreme.⁷

ArtVI.C2.3.2 Dual Federalism in Late Nineteenth and Early Twentieth Centuries

The Supreme Court continued to apply the basic principle of federal supremacy throughout the late nineteenth and early twentieth centuries. But the Supremacy Clause’s role during that era was limited by other aspects of the Court’s federalism jurisprudence. Throughout this period, the Court embraced what academics have called the doctrine of “dual federalism,” under which the federal government and the states occupied largely distinct, non-overlapping zones of constitutional authority.¹ Applying this framework, the Court adopted a narrow interpretation of Congress’s Commerce Clause authorities² and construed the Tenth Amendment as imposing strict additional limitations on federal power.³ The Court also relied on the Dormant Commerce Clause to conclude that states lacked the power to regulate certain subjects of exclusive federal concern.⁴ While federal supremacy thus persisted as a background principle during the late nineteenth and early twentieth centuries, the Court’s bifurcation of federal and state authority minimized the instances in which the two could conflict.⁵

To the extent that the Supremacy Clause played an explicit role in the federalism disputes of this era, the Court applied it in ways that reinforced the sharp division of federal and state power. In a series of early-twentieth-century decisions, the Court developed a precursor to the doctrine of “field preemption”—the principle that some federal legislation implicitly prevents states from adopting any laws regulating the same general subject. For example, in Southern Railway v. Reid, the Court held that the Interstate Commerce Act (ICA)—which regulated railroad rates—superseded a state law requiring railroads to transport tendered freight.⁶ The Court reasoned that Congress had “taken possession of the field” of railroad rate regulation with the ICA, thereby precluding even supplementary state regulations.⁷ In another decision, the Court held that a different federal law requiring railroads to secure the safe transportation of property upon reasonable terms displaced a state law compelling railroads to settle certain claims within forty days.⁸ In his opinion for the Court, Justice Oliver Wendell Holmes rejected the argument that the state law did not conflict with the federal law, explaining that the absence of such a conflict was “immaterial,” because “coincidence is as ineffective as opposition” when “Congress has taken [a] particular subject-matter in hand.”⁹ In yet another field-preemption case, the Court held that a federal law involving railroads’ liability for employee injuries superseded state common law claims based on such injuries.¹⁰

While the Supreme Court’s reasoning in these cases varied, one commentator has noted the readiness with which the Court concluded that federal law preempted the relevant fields.¹¹ For example, in one decision, the Court appeared to suggest that any federal legislation in certain fields precluded states from adopting even supplementary regulations of the same subject.¹² Under this theory of “automatic” preemption, Congress’s authority over certain subjects was one of “latent exclusivity,” meaning “the power of the states ended as soon as Congress chose to exercise its regulatory power” in those fields.¹³ However, this view of federal power—which was related to notions of dual federalism—would soon give way to broader legal and political trends.

ArtVI.C2.3.3 New Deal and Presumption Against Preemption

The Supreme Court abandoned dual federalism during the New Deal era of the 1930s and 1940s. In those years, the Court acceded to demands for a more active national government by revising its Commerce Clause and Tenth Amendment jurisprudence.¹ The federal government thereby gained vast new powers to regulate the economy, which it deployed in new and creative ways.² But this expansion of federal authority threatened sweeping consequences when paired with the Court’s aggressive application of the Supremacy Clause. Specifically, if field preemption automatically followed from many types of federal legislation, Congress’s enhanced powers would displace large swathes of state regulation—even in cases when state regulation did not conflict with federal law. To avoid this outcome, the New Deal Court retreated from dual federalist notions of “latent exclusivity,” clarifying that federal law displaced state law only if Congress’s intention to do so was clear.

In Mintz v. Baldwin, for example, the Court rejected the argument that a federal law regulating the inspection and transportation of cattle superseded a state order compelling certain breeders to remove uncertified cattle from the state.³ In rejecting this argument, the Court explained that “[t]he purpose of Congress to supersede or exclude state action against the ravages of disease is not lightly to be inferred,” and that “[t]he intention so to do must definitely and clearly appear.”⁴ The Court endorsed a similar principle in Rice v. Santa Fe Elevator Corp., where it held that the federal Warehouse Act superseded some—but not all—state law claims against grain-warehouse operators.⁵ The Court explained that, in evaluating whether federal law displaces state law, it “start[ed] with the assumption that the historic police powers of the States were not to be superseded . . . unless that was the clear and manifest purpose of Congress.”⁶ The Court continues to apply this “presumption against preemption” to this day-albeit in limited circumstances.⁷

ArtVI.C2.3.4 Modern Doctrine on Supremacy Clause

Since the mid-twentieth century, the Supreme Court has channeled its Supremacy Clause jurisprudence into the language of “federal preemption.”¹ The Court’s cases identify several types of preemption. At the highest level of generality, federal law can preempt state law either expressly or impliedly. Federal law expressly preempts state law when it contains explicit language to that effect.² By contrast, federal law impliedly preempts state law when that intent is implicit in its structure and purpose.³

The Court has also distinguished between different forms of implied preemption. As noted, field preemption occurs where federal law is “so pervasive as to make reasonable the inference that Congress left no room for the States to supplement it,” or where “the federal interest is so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject.”⁴ In contrast, conflict preemption occurs where compliance with federal and state law is impossible (“impossibility preemption”) or where state law poses an obstacle to federal objectives (“obstacle preemption”).⁵

In all preemption cases, “the purpose of Congress is the ultimate touchstone” of the Court’s statutory analysis.⁶ In analyzing congressional purpose, the Court continues to invoke the presumption against preemption from Mintz and Rice—albeit in limited circumstances. While the Court regularly employed this presumption in the 1980s and 1990s,⁷ it has invoked it less consistently in recent years.⁸ Moreover, in a 2016 decision, the Court departed from prior case law⁹ when it explained that the presumption does not apply in express-preemption cases.¹⁰ The Court has also acknowledged exceptions to the presumption in cases involving subjects that the states have not traditionally regulated,¹¹ and cases involving subjects in which the federal government has historically had a significant regulatory presence.¹² Accordingly, while the presumption remains relevant in certain implied-preemption disputes,¹³ the Court has narrowed the circumstances in which it applies.

As the federal government’s regulatory role has expanded, preemption has become a ubiquitous feature of the modern administrative state. Preemptive federal statutes now shape the regulatory environment for most major industries, including pharmaceutical drugs, securities, nuclear safety, medical devices, air transportation, banking, automobiles, and telecommunications.¹⁴ While preemption is thus a pervasive feature of the contemporary legal landscape, the Supremacy Clause’s role in modern legal doctrine differs from that of many other constitutional provisions. Preemption cases are primarily exercises in statutory interpretation—not constitutional analysis. Generally, litigants do not dispute the Supremacy Clause’s meaning or advance conflicting theories on its scope. The basic principle enshrined in the Clause—federal supremacy—is now well-settled. As a result, the Supremacy Clause does not play a central role in modern debates over federalism; those battles are instead typically fought on the terrain of the Commerce Clause, the Spending Clause, and the Fourteenth Amendment.¹⁵ Today, preemption cases ordinarily turn on the same types of issues—like the textualist/purposivist divide and administrative deference—that recur in all manner of statutory litigation.¹⁶ But the Supremacy Clause’s modern role as a background principle hardly negates its importance. Federal supremacy remains a foundational doctrine of constitutional law that undergirds much of the modern regulatory state.