Updated: October 26, 2026
The Tenth Amendment says that powers the Constitution does not give to the federal government, and does not forbid to the states, are reserved to the states or to the people. On its own it grants nothing new. Its practical force comes from how the Supreme Court has read it: Congress can reach far through the Commerce Clause and its spending power, but it cannot order state legislatures or state officers to carry out federal programs, and it cannot attach conditions to federal money that amount to coercion.
The full text, ratified on December 15, 1791, with the rest of the Bill of Rights, is one sentence: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.” This guide covers what that sentence has meant in court, where the line between federal and state power sits today, and how to tell which government is responsible for a problem you have.
Three ideas the amendment rests on
- Enumerated powers. Congress has only the powers listed in the Constitution, mostly in Article I, Section 8, plus what is “necessary and proper” to carry them out. Our guide to enumerated and implied powers explains how far that second phrase reaches.
- Reserved powers. Everything else — the general police power over health, safety, family law, most crime, licensing and schools — stays with the states unless the Constitution takes it away.
- Federal supremacy. Where Congress acts within its powers, federal law wins over conflicting state law under Article VI. The Tenth Amendment does not let a state override a valid federal statute; see our explainer on the Supremacy Clause.
The amendment deliberately left out one word. The Articles of Confederation had reserved to the states every power not “expressly” delegated. The Tenth Amendment does not say “expressly,” and in McCulloch v. Maryland (1819) the Court treated that omission as the reason implied federal powers are allowed.
The cases that defined it: a timeline
| Year | Case and citation | What the Court held |
|---|---|---|
| 1819 | McCulloch v. Maryland, 17 U.S. 316 | Congress could charter a national bank as an implied power; the amendment’s omission of “expressly” leaves the scope of federal power to a fair reading of the whole Constitution. |
| 1941 | United States v. Darby, 312 U.S. 100 | Upheld federal wage-and-hour rules; the amendment “states but a truism” that all is retained which has not been surrendered. |
| 1942 | Wickard v. Filburn, 317 U.S. 111 | Wheat grown for use on one’s own farm could be regulated because, added up nationally, it substantially affects interstate commerce. |
| 1976 | National League of Cities v. Usery, 426 U.S. 833 | Federal wage rules could not reach “traditional governmental functions” of states. |
| 1985 | Garcia v. San Antonio Metropolitan Transit Authority, 469 U.S. 528 | Overruled Usery nine years later as unworkable; states are protected mainly by their role in the national political process. |
| 1987 | South Dakota v. Dole, 483 U.S. 203 | Congress may withhold 5% of federal highway funds from states with a drinking age under 21; spending conditions are valid if clear, related to the federal interest and not coercive. |
| 1992 | New York v. United States, 505 U.S. 144 | Congress cannot require a state to take title to low-level radioactive waste or legislate on Congress’s orders — the start of the modern anti-commandeering rule. |
| 1995 | United States v. Lopez, 514 U.S. 549 | Struck down a federal ban on guns near schools: possession in a school zone is not economic activity that Congress can reach through the Commerce Clause. |
| 1997 | Printz v. United States, 521 U.S. 898 | Congress cannot require local law-enforcement officers to run federal background checks. |
| 2012 | National Federation of Independent Business v. Sebelius, 567 U.S. 519 | Threatening a state’s existing Medicaid funding to force it to adopt the Medicaid expansion was unconstitutionally coercive; the expansion became optional for states. |
| 2018 | Murphy v. National Collegiate Athletic Association | A federal law forbidding states to authorize sports betting violated the anti-commandeering rule (7–2); the whole statute fell (6–3). |
Read as a sequence, the cases show two separate questions. One is how far Congress’s own powers extend — Wickard broadly, Lopez less so. The other is what Congress may make state governments do — and there the line has held firm since 1992: Congress may regulate people directly, offer money with conditions, or pre-empt state law, but it may not commandeer state legislatures or officials. The Commerce Clause side of this story is told in our guide to the Commerce Clause.
Three ways Washington can influence states — and the one it cannot use
| Tool | Allowed? | Example |
|---|---|---|
| Regulate individuals and businesses directly under an enumerated power | Yes | Federal wage-and-hour law upheld in Darby |
| Attach clear, related conditions to federal grants | Yes, unless coercive | Highway money and the drinking age in Dole; the Medicaid threat in NFIB went too far |
| Pre-empt state law in a field Congress may regulate | Yes | Valid federal statutes displace conflicting state rules under the Supremacy Clause |
| Order states to legislate or state officers to enforce federal law | No | New York (1992), Printz (1997), Murphy (2018) |
This is why a uniform national drinking age exists without a federal drinking-age law: it was achieved through a funding condition that every state chose to meet. It is also why states can decline to have their own officers enforce some federal programs while federal agents remain free to enforce federal law within that state.
How this affects you: which government is responsible?
Most of the rules that touch daily life come from state law, applied by state and local offices. A quick way to find the right door:
- Mainly state (reserved powers): driver’s licences and vehicle registration, marriage and divorce, most criminal law and policing, professional and business licences, public schools, property and contract law, and running elections, including federal ones.
- Mainly federal (enumerated powers): passports and immigration, federal taxes, Social Security and Medicare, the postal service, interstate trade rules and federal crimes.
- Shared, through grants: highways, Medicaid, unemployment insurance and many education programs — federal money and minimum rules, administered by the state. For problems here, start with the state agency that runs the program.
Within a state, power is divided again: cities and counties have only what the state grants them. That second layer is explained in our guide to home rule for cities.
Common misconceptions
- “The Tenth Amendment lets a state ignore federal law.” No. Nullification was rejected in Cooper v. Aaron (1958), which rested on the Supremacy Clause. A state may decline to help enforce a federal program, but the federal law still applies to people in that state.
- “States’ rights and individual rights are the same thing.” The Tenth Amendment protects the structure of government. Individual rights against states come mainly from the Fourteenth Amendment, covered in our guide to what the Fourteenth Amendment changed.
- “Anything not in the Constitution belongs to the states.” Powers can also be implied from the enumerated ones, and the amendment itself reserves powers “to the people” as well as to the states.
Frequently asked questions
What is the purpose of the Tenth Amendment?
What powers does the Tenth Amendment give to the states?
How does the Tenth Amendment protect states’ rights?
Can the federal government force states to enforce federal laws?
Is the drinking age of 21 a federal law?
Sources
Tenth Amendment (Constitution Annotated) · National Archives: Bill of Rights transcript