What Is the Law of the Land? Supremacy Clause

Last reviewed: October 17, 2026. This article is general information, not legal advice. Whether a particular federal law overrides a state law depends on the exact statutes involved, so speak to a lawyer about a real dispute.

You'll hear "the law of the land" in news coverage, civics classes and political speeches, usually about the Constitution or a big Supreme Court ruling. It's a real legal phrase, and it comes straight from the text of the US Constitution.

Short answer: What is the law of the land? In the United States, it is the Constitution, the federal laws made in line with it, and treaties made under the authority of the United States. Article VI, Clause 2, known as the Supremacy Clause, calls these "the supreme Law of the Land" and says judges in every state must follow them even if a state's own constitution or laws say otherwise.

What counts as "the law of the land"

The clause names three things:

The Constitution itself. It sits at the top. A federal law that conflicts with the Constitution is not valid, which is why the clause only covers federal laws "made in Pursuance thereof".
Federal laws made under the Constitution. Statutes passed by Congress within its constitutional powers.
Treaties made under the authority of the United States.

It does not make the federal government all-powerful. Congress can only legislate within the powers the Constitution gives it, and outside those powers states make their own laws.

For where the clause sits in the Constitution and how it is read, see which article proclaims the Constitution as the highest law?

How it works in practice: preemption

When a valid federal law and a state law clash, the federal law wins. Lawyers call this preemption. In Arizona v. United States (2012), the Supreme Court summarized the main ways it happens:

Express preemption. Congress writes into a statute that state laws on the subject are displaced.
Field preemption. Federal regulation of an area is so complete, or the federal interest so dominant, that there is no room left for states to add their own rules.
Conflict preemption. State law gives way when it conflicts with federal law, including when it stands "as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress."

In that case the Court held that three provisions of an Arizona immigration law were preempted by federal law, while declining to block a fourth at that early stage.

What this means for you

Most everyday law is still state law. Crimes like theft and assault, marriage and divorce, driving rules and most contracts are mainly governed by your state.
Federal law still applies inside every state. Something can be allowed under state law and still be illegal under federal law. Marijuana is the best-known example: a state can stop prosecuting it under state law, but that doesn't change federal law. See are edibles legal? for how that plays out.
A state law isn't automatically void just because a federal law exists on a similar topic. Courts look at what Congress intended and whether there's a real conflict.

Where the phrase comes from

"The law of the land" is older than the Constitution. In the 1297 version of Magna Carta, as translated by the National Archives, the king promises that no free man will be imprisoned, outlawed or "in any way ruined" except "by lawful judgement of his peers or by the law of the land."

That idea, that the government can only act against you according to established law, carried over to America. The Fifth Amendment says no person shall "be deprived of life, liberty, or property, without due process of law," and the Fourteenth Amendment says "nor shall any State deprive any person of life, liberty, or property, without due process of law."

So the phrase has two related meanings:

The supreme law of the country, as in the Supremacy Clause.
Lawful process, as in Magna Carta and its American descendant, due process.

Common misunderstandings

"Whatever the President orders is the law of the land." Executive orders can have legal force, but only within the authority the Constitution and Congress give the President, and courts can block orders that go beyond it.
"States can nullify federal laws." They can't cancel valid federal law by passing their own. They can challenge it in court or ask Congress to change or repeal it.
"Once something is the law of the land, it's permanent." Statutes can be amended or repealed, Supreme Court interpretations can change, and the Constitution itself can be amended under Article V.

What does "the law of the land" mean in the United States?

It refers to the US Constitution, federal laws made in line with it, and treaties made under the authority of the United States. Article VI, Clause 2 (the Supremacy Clause) calls these "the supreme Law of the Land" and says state judges are bound by them.

Is a Supreme Court decision the law of the land?

People often say so informally. Strictly, the Supremacy Clause names the Constitution, federal laws and treaties. But when the Supreme Court interprets the Constitution or a federal law, lower courts across the country must follow that interpretation, so in practice its rulings bind everyone until the Court changes its view or the law is changed.

Does federal law always override state law?

No. Only valid federal law wins, and only where it actually displaces state law: because Congress said so expressly, because federal law occupies the whole field, or because the two laws conflict. In many areas, such as most crimes, family law and traffic rules, states make their own laws.

Can a state ignore a federal law it disagrees with?

Not by passing a contrary law. Article VI says valid federal law governs "any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." A state can challenge a federal law in court or ask Congress to change it, but a state statute cannot cancel a valid federal one.

Where does the phrase "law of the land" come from?

From English law. The 1297 version of Magna Carta, as translated by the National Archives, promises that no free man will be imprisoned or harmed "save by lawful judgement of his peers or by the law of the land." The US Constitution expresses a similar protection through the phrase "due process of law."

What Is the Law of the Land? The Supremacy Clause in Plain English

What counts as "the law of the land"

How it works in practice: preemption

What this means for you

Where the phrase comes from

Common misunderstandings

Sources

About Farrukh Shahzad

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