Why Is the Constitution the Supreme Law of the Land?
Before the Constitution existed, the United States nearly collapsed under a system that treated federal authority as optional. States ignored congressional requisitions for funds, printed competing currencies, and passed debtor-relief laws that openly violated the Treaty of Paris of 1783. Madison described federal law under the Articles of Confederation as merely "recommendatory" rather than binding. The union was dissolving not from external attack but from internal structural failure.
The Supremacy Clause of Article VI was the Framers' direct response to that crisis. It was not a philosophical abstraction. It was a structural repair, engineered to ensure that the Constitution is the supreme law of the land because a system without that guarantee had already been tried and had failed. Hamilton argued in Federalist No. 33 that supremacy was not a new grant of power but the logical consequence of creating a national government at all.
The principle traces from its historical origins through its constitutional text, its enforcement through judicial review, its operational expression in preemption doctrine, and its structural limits under the anti-commandeering doctrine. Understanding why the Constitution holds supreme authority requires engaging with the cases, the text, and the political theory that sustain it.
From Confederation to Constitution: Why Supremacy Became Necessary
The Articles of Confederation created a political system designed to fail. Congress could request but never compel. It could recommend but never enforce. The result was predictable and catastrophic.
States imposed tariffs on each other's goods, turning the confederation into a collection of competing commercial sovereignties. New York taxed goods arriving from New Jersey and Connecticut. States printed their own currencies, creating inflationary chaos. When Congress assessed requisitions to fund the Continental Army's debts, states simply declined to pay. The Articles lacked any provision declaring federal law superior to state law, and without that provision, federal authority evaporated at the state line.
The crisis was existential, not merely administrative. States passed debtor-relief laws that directly violated the Treaty of Paris, the agreement that had secured American independence from Britain. Foreign creditors had no recourse. The nation's international credibility depended on a structural guarantee that federal commitments would bind the states, and no such guarantee existed.
John Locke's Second Treatise of Government (1690) established that legitimate government rests on a social contract, and that a government exceeding that contract loses its claim to obedience. The Framers extended this logic. The Constitution would derive its authority not from state governments but from the people directly. "We the People" signaled that the Constitution, ratified through state conventions rather than state legislatures, possessed a higher democratic legitimacy than any ordinary state statute.
Madison's reasoning was precise. The people's expressed will, embodied in the Constitution, must be superior to the legislature's will, embodied in ordinary statutes. No state legislature can override the Constitution without overriding the people themselves.
This logic is not uniquely American. Bangladesh's Constitution, adopted on November 4, 1972, emerged from the Liberation War of 1971 — a context of constitutional rupture far more violent than the American experience, but governed by the same foundational question. The framers of Bangladesh's constitution answered it with Article 7(1): "All powers in the Republic belong to the people, and their exercise on behalf of the people shall be effected only under, and by the authority of, this Constitution." Article 7(2) completes the architecture: "This Constitution is, as the solemn expression of the will of the people, the supreme law of the Republic, and if any other law is inconsistent with this Constitution that other law shall, to the extent of the inconsistency, be void." The language mirrors the American logic precisely. Constitutional supremacy derives from popular sovereignty. The constitution is supreme because it is the people's law, not the government's creation. Where the U.S. Framers were reacting to the inadequacy of the Articles of Confederation, Bangladesh's framers were constructing a legal order from the ground up after a genocidal war. Both responses produced the same structural answer: the constitution must stand above all other law, or it stands for nothing.
Hamilton made the structural argument in Federalist No. 33. If the federal government possesses legitimate constitutional authority, then laws made pursuant to that authority must be supreme. The alternative is not a balance of power but a contradiction: a government that can legislate but whose legislation can be ignored. Madison reinforced this in Federalist No. 44, warning that without supremacy, the Constitution would be subordinate to state constitutions, reducing the federal government to a treaty partner rather than a sovereign authority. As Madison put it, the "authority of the whole society" would be "everywhere subordinate to the authority of the parts."
The Framers did not stumble into supremacy. They built it deliberately, as the structural prerequisite for a functioning national government.
Article VI and the Supremacy Clause: Text and Structure
The Supremacy Clause is Article VI, Clause 2 of the Constitution. Its full text deserves careful reading:
> "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."
Luther Martin introduced this clause at the Constitutional Convention on July 17, 1787. It passed unanimously. That unanimity is significant. Even delegates who disagreed on the scope of federal power agreed that whatever power the federal government possessed must be supreme within its domain.
The clause establishes a precise three-tier hierarchy. At the apex sits the Constitution itself. Below it stand federal statutes "made in Pursuance thereof." Below those stand treaties made "under the Authority of the United States." The phrase "in Pursuance thereof" is not decorative. It limits federal supremacy to laws that are themselves constitutional. A federal statute that exceeds Congress's enumerated powers does not qualify as supreme law. This phrase anticipates judicial review, building into the text a mechanism for challenging federal overreach.
"Judges in every State shall be bound thereby" makes the Supremacy Clause self-executing. It does not require state legislatures to pass implementing legislation. It does not depend on state cooperation. It operates directly on state judicial officers, commanding them to apply federal law over contrary state law. In 1787, this was radical. It bypassed state political processes entirely, creating a direct legal obligation that no state institution could mediate.
Gouverneur Morris refined the clause's language during drafting, changing "supreme Law of the several states" to "supreme Law of the Land." Federal authority runs over the states, not through them. The law of the land is a single, nationally binding legal order, not a collection of state-filtered interpretations.
The Oath Clause in Article VI, Clause 3 reinforces this structure. All state legislative, executive, and judicial officers must swear to support the Constitution. Hamilton noted in Federalist No. 27 that this oath makes state officials "auxiliary to the enforcement" of federal law. The obligation is personal, not merely institutional. Every state officer who takes that oath assumes an individual duty to uphold constitutional supremacy.
Text without enforcement is aspiration. The Supremacy Clause needed a mechanism to give it operational force.
Judicial Review as the Enforcement Mechanism: Marbury and Its Legacy
In 1803, Chief Justice John Marshall faced a politically impossible case. William Marbury demanded his judicial commission. President Jefferson's Secretary of State, James Madison, refused to deliver it. If Marshall ordered delivery, Jefferson would ignore the order, humiliating the Court. If Marshall declined to act, the Court would appear powerless.
Marshall's solution in Marbury v. Madison, 5 U.S. (1 Cranch) 137 (1803), was to claim a far greater power by ruling against his own jurisdiction. He held that Section 13 of the Judiciary Act of 1789 conflicted with Article III. Because the Constitution is supreme, the statute was void. Marshall's declaration has echoed for over two centuries: "It is emphatically the province and duty of the judicial department to say what the law is."
This connected directly to the "in Pursuance thereof" language of Article VI. A federal law that contradicts the Constitution is not made in pursuance of it. Judicial review became the enforcement mechanism the Supremacy Clause required.
Sixteen years later, Marshall applied the Supremacy Clause against state action in McCulloch v. Maryland, 17 U.S. (4 Wheat.) 316 (1819). Maryland had imposed a tax on the Second Bank of the United States. Marshall struck it down, reasoning that a state cannot tax a federal instrumentality because "the power to tax involves the power to destroy." If states could tax federal institutions out of existence, federal supremacy would be a dead letter. McCulloch operationalized the Supremacy Clause as a shield against state interference with legitimate federal operations.
Martin v. Hunter's Lessee, 14 U.S. (1 Wheat.) 304 (1816), addressed a different structural problem. If state courts could interpret federal law without any appellate check, the "supreme Law of the Land" would mean different things in different states. Justice Story's opinion established that the Supreme Court possesses appellate jurisdiction over state courts on questions of federal law. Uniformity of interpretation is a structural necessity inherent in supremacy itself.
Cooper v. Aaron, 358 U.S. 1 (1958), brought the logical arc to its culmination. Arkansas officials claimed the authority to resist Brown v. Board of Education through state legislation. All nine justices signed the opinion, declaring that the Supreme Court's interpretation of the Constitution binds every government actor, not just the parties to a particular case. The Court definitively rejected nullification: no state can declare federal law inapplicable within its borders. The Supremacy Clause, enforced through judicial review, does not permit selective compliance.
Federal Preemption Doctrine: How Supremacy Displaces State Law
Preemption is the Supremacy Clause in action. It is the doctrinal framework courts apply when federal and state law conflict, and it determines when federal law displaces state law entirely.
The doctrine operates through four recognized categories, each with distinct analytical requirements.
Express preemption is the most straightforward. Congress includes explicit statutory language declaring that federal law displaces state law in a defined area. ERISA Section 514(a), for example, expressly preempts state laws that "relate to" employee benefit plans. The analytical task is statutory interpretation: courts determine the scope of the preemption provision by parsing its text. When Congress speaks clearly, the inquiry is relatively contained.
Field preemption applies when Congress has not expressly preempted state law but has regulated so pervasively that it impliedly occupies the entire field. The Supreme Court articulated a three-factor test in Pennsylvania v. Nelson, 350 U.S. 497 (1956): whether the federal regulatory scheme is sufficiently pervasive, whether the federal interest is sufficiently dominant, and whether state law creates a danger of conflict with federal administration. Field preemption governs areas like immigration regulation and nuclear power, where federal authority is comprehensive and state regulation would fragment a necessarily national scheme.
Conflict preemption divides into two subtypes. Impossibility preemption applies when simultaneous compliance with both federal and state law is physically impossible. If federal law requires X and state law prohibits X, one must yield, and under Article VI, state law yields.
Obstacle preemption, the more contested subtype, applies when state law "stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress," as the Court recognized in Hines v. Davidowitz, 312 U.S. 52 (1941). In Geier v. American Honda Motor Co., 529 U.S. 861 (2000), the Court held that a state tort suit requiring airbags in all cars conflicted with a federal standard that deliberately allowed manufacturers a range of passive restraint options. Justice Thomas has criticized obstacle preemption as an open-ended judicial invention that lets courts invalidate state laws based on speculative assessments of congressional purpose. The modern Court has responded by requiring increasingly high thresholds before finding obstacle preemption.
The presumption against preemption operates as a counterweight. In areas of traditional state regulation, such as health, safety, and family law, courts presume that Congress did not intend to displace state authority absent a clear statement. As the Court held in Medtronic, Inc. v. Lohr, 518 U.S. 470 (1996), this presumption reflects the constitutional design: federalism is a liberty-protecting arrangement, and preemption doctrine must respect it.
The Anti-Commandeering Doctrine: Structural Limits on Federal Supremacy
Federal supremacy means federal law prevails over contrary state law. It does not mean the federal government can conscript state governments to implement federal policy. This distinction, the anti-commandeering doctrine, is one of the most important structural limits on federal power.
The doctrine emerged in New York v. United States, 505 U.S. 144 (1992). Congress had required states to either regulate radioactive waste disposal according to federal standards or "take title" to the waste generated within their borders. Justice O'Connor's majority opinion struck down the take-title provision: "The Federal Government may not compel the States to enact or administer a federal regulatory program." Congress can incentivize. Congress can regulate private conduct directly. But Congress cannot turn state legislatures into instruments of federal policy.
Printz v. United States, 521 U.S. 898 (1997), extended this principle to state executive officers. The Brady Handgun Violence Prevention Act required local sheriffs to conduct background checks on prospective handgun purchasers. Justice Scalia's majority opinion struck down this requirement as "fundamentally incompatible with our constitutional system of dual sovereignty." The federal government cannot commandeer state executive officials any more than it can commandeer state legislatures.
The doctrine's most significant expansion came in Murphy v. NCAA, 584 U.S. 453 (2018). The Professional and Amateur Sports Protection Act (PASPA) prohibited states from authorizing sports gambling, blocking New Jersey's effort to legalize sports betting at its casinos and racetracks. PASPA did not regulate private conduct. It ordered states not to change their own laws. Justice Alito's majority opinion held that the anti-commandeering doctrine applies equally whether Congress compels states to act or compels them to refrain from acting. The distinction between commanding action and commanding inaction is irrelevant. Both constitute impermissible federal dictation of state policy. Alito identified three structural purposes the doctrine serves: it protects individual liberty through diffusion of power, it maintains political accountability by preventing Congress from shifting regulatory costs to states, and it prevents Congress from circumventing the legislative process.
The doctrine has boundaries. Reno v. Condon, 528 U.S. 141 (2000), upheld the Driver's Privacy Protection Act, which restricted states' ability to sell driver information. The Court distinguished this from commandeering because the Act regulated states as owners of databases, just as it would regulate private entities holding similar data. The line is clear in principle: generally applicable laws that regulate states alongside private parties are permissible. Laws that single out state governments and dictate their regulatory choices are not.
Modern Implications: Constitutional Supremacy in Practice
Litigants actively contest constitutional supremacy, and its doctrinal architecture structures some of the most consequential legal disputes in American law.
Federal cannabis prohibition illustrates the practical complexity. The Controlled Substances Act classifies marijuana as a Schedule I substance. Yet a majority of states have legalized cannabis for medical or recreational use. The federal government has not ordered states to criminalize marijuana, so this is not a commandeering problem. States can remove their own criminal penalties. But the Supremacy Clause means federal enforcement agents can still arrest individuals for conduct that state law permits. Federal banking and money laundering statutes compound the tension: financial institutions serving cannabis businesses risk federal prosecution even where state law authorizes the activity. The result is a legal patchwork where supremacy is formally intact but practically attenuated by enforcement discretion.
Immigration enforcement presents the anti-commandeering doctrine in sharp relief. Federal supremacy over immigration law is well established. But sanctuary jurisdictions that decline to assist federal immigration enforcement rely on the principle that the federal government cannot commandeer state and local officers to carry out federal enforcement priorities. The tension is structural, not aberrational. It is precisely what the anti-commandeering doctrine contemplates: federal law is supreme, but the federal government must enforce it with its own resources.
The principle that constitutional supremacy requires an independent judiciary willing to enforce it is tested most severely when courts confront not ordinary legislation but constitutional amendments enacted by governments attempting to legitimate prior illegal rule. Bangladesh provides one of the most consequential modern examples. Between 1975 and 1990, Bangladesh endured successive military governments that suspended the constitution and governed through martial law proclamations. The Fifth Amendment to the Constitution of Bangladesh, enacted in 1979 by a military-aligned parliament, attempted to validate those martial law periods retroactively by incorporating the proclamations into the constitutional text. The strategy was transparent: if you cannot justify unconstitutional rule, amend the constitution to declare it was constitutional all along.
The Appellate Division of Bangladesh's Supreme Court rejected this approach in Khondker Delwar Hossain v. Bangladesh Italian Marble Works Ltd., 62 DLR (AD) 298 (2010). The Court struck down the Fifth Amendment, holding that martial law proclamations and military governance were fundamentally incompatible with constitutional supremacy. No subsequent amendment could launder unconstitutional rule into constitutional authority. The Court invoked the basic structure doctrine: certain core features of the constitution — popular sovereignty, the rule of law, judicial independence, fundamental rights — cannot be abrogated even by formal amendment, because they are the constitution's foundational commitments rather than ordinary provisions subject to revision. The judgment restored the constitutional text to its 1972 form. It is, in structure, the Bangladesh equivalent of Cooper v. Aaron: a court declaring that constitutional supremacy is not a political option that governments may accept or reject but a legal obligation that the judiciary will enforce regardless of who holds executive power. The lesson the Italian Marble case teaches is the same one Marbury taught two centuries earlier. Constitutional supremacy means nothing if courts defer to power rather than to law.
Emerging areas of federal regulation create new preemption battlegrounds. State laws governing artificial intelligence, data privacy, and autonomous vehicles increasingly collide with federal regulatory frameworks. Whether Congress has occupied these fields or state regulation merely supplements federal standards will generate preemption litigation for years.
For practicing attorneys, the Supremacy Clause generates daily tactical decisions. Preemption is a standard defense in products liability, pharmaceutical regulation, financial services, and environmental law. The presumption against preemption in areas of traditional state regulation shapes how courts evaluate those arguments, often determining outcomes before the merits are reached.
The doctrinal architecture is coherent. The Supremacy Clause establishes the hierarchy. Judicial review enforces it. Preemption operationalizes it when federal and state law collide. The anti-commandeering doctrine preserves the dual sovereignty the Constitution demands. Each element depends on the others. Remove judicial review, and supremacy is unenforceable. Remove anti-commandeering, and federalism collapses into a unitary system the Framers rejected.
The Federalist Papers on Constitutional Supremacy: Hamilton and Madison's Arguments
The Supremacy Clause was controversial at ratification. Anti-Federalists saw it as a death warrant for state sovereignty, a mechanism by which the new federal government would absorb all governmental power. Hamilton and Madison's responses in the Federalist Papers remain the most authoritative defense of constitutional supremacy, and courts continue to cite them.
Hamilton addressed the objection directly in Federalist No. 33. The Supremacy Clause "is not a grant of new power" but the logical consequence of establishing a national government with defined authorities. If the Constitution grants Congress the power to tax, then tax laws made pursuant to that power must be supreme. The alternative is incoherence: a government with the power to legislate but without the power to make its legislation effective. Hamilton also anticipated the limiting principle. A law that exceeds constitutional authority "would not be the supreme law of the land, but a usurpation of power not granted by the Constitution." This argument maps precisely onto the "in Pursuance thereof" language of Article VI.
Madison's defense in Federalist No. 44 took a different angle. He asked his readers to consider the consequences of the alternative. Without the Supremacy Clause, the "authority of the whole society" would be "everywhere subordinate to the authority of the parts." The federal government would be reduced from a sovereign to a treaty partner dependent on state goodwill for enforcement of its laws. The ratification process answered this concern structurally: because the people, not the state governments, ratified the Constitution, it carries a democratic legitimacy that state resistance cannot override.
Hamilton returned to the theme in Federalist No. 78, arguing that the judiciary must serve as the "bulwark" against legislative encroachments on the Constitution. Courts must treat the Constitution as "paramount law" and refuse to enforce statutes that contradict it. This was the intellectual foundation for judicial review, which Marshall realized sixteen years later in Marbury v. Madison. Hamilton identified the institutional mechanism, an independent judiciary, that would make supremacy enforceable rather than aspirational.
Modern courts analyzing supremacy questions operate within the framework Hamilton and Madison constructed: supremacy is structural, not arbitrary; it extends only to legitimate exercises of federal power; and an independent judiciary is its necessary guardian.