The Tenth Amendment reserves every power the Constitution does not give to the federal government, and does not forbid to the states, to the states or to the people. Ratified in 1791 as part of the Bill of Rights, it is the constitutional statement of American federalism: Washington gets a listed set of powers, and everything else is left to state governments or to individual citizens.
The Text and What It Means
The amendment 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.”1National Archives. The Bill of Rights: A Transcription
Read carefully, it does two things at once. It caps federal power at the list the Constitution actually hands over, and it presumes that any remaining authority sits with the states or the people. It does not create new state powers. It confirms that states already have them.
Delegated, Reserved, and Shared Powers
The Constitution gives the federal government a specific list of powers, often called “enumerated” or “delegated.” Most appear in Article I, Section 8, and include coining money, declaring war, and regulating interstate commerce. The same section lets Congress pass laws “necessary and proper” to carry out those listed powers, which is where much of the tension with the Tenth Amendment lives.2U.S. Constitution Annotated | US Law | LII / Legal Information Institute. Section 8 Enumerated Powers
Reserved powers are not itemized anywhere. They are the leftovers. A state does not need a constitutional provision authorizing it to legislate; it has inherent authority to govern unless the Constitution specifically forbids the action. That is why states can regulate things the Constitution never mentions.
Some powers are shared. Both levels of government can tax income, build roads, borrow money, and run courts. These are called concurrent powers, and when both governments act in the same space, a separate set of rules decides which law controls.
What States Actually Do With Reserved Powers
States govern daily life through what courts call the “police power”: broad authority to legislate for the health, safety, morals, and general welfare of residents. In practice, that covers:
- Licensing professions such as medicine, law, and the trades, and setting the terms of practice.
- Running public education, including school-year length, graduation requirements, curriculum standards, and funding formulas.
- Writing and enforcing criminal codes, including offenses, sentences, and fines.
- Regulating property and land use through zoning, building codes, and real estate rules.
- Administering elections, including registration rules, polling locations, and ballot design, even for federal races.
Keeping these functions at the state level lets governance reflect local priorities. A rural state may approach land use very differently from a densely populated one, and the amendment preserves room for that.
When Federal Law Overrides State Law
The Tenth Amendment does not give states the last word on every subject. Article VI’s Supremacy Clause declares federal law “the supreme law of the land” and binds state judges to it regardless of anything in a state’s own laws or constitution.3US Law | LII / Legal Information Institute. Article VI When a valid federal law conflicts with a state law, the federal law wins. This is called preemption.
Preemption comes in different forms. Congress sometimes says explicitly that federal law displaces state regulation in an area. Other times it is implied, either because federal regulation is so thorough that no room is left for state rules, or because a state law directly contradicts a federal requirement.4Legal Information Institute (LII) / Cornell Law School. Preemption Where Congress has not made its intent clear, courts generally try to avoid preempting state law.
The Commerce Clause is the most common source of federal authority that bumps into reserved powers. In United States v. Lopez (1995), the Supreme Court struck down the Gun-Free School Zones Act, holding that carrying a gun near a school was not an economic activity with a substantial connection to interstate commerce.5Justia U.S. Supreme Court Center. United States v. Lopez A decade later, Gonzales v. Raich (2005) went the other way, allowing federal drug laws to override California’s medical marijuana law because the national drug market was interconnected enough to fall within the Commerce Clause.6Justia U.S. Supreme Court Center. Gonzales v. Raich The line between federal and state authority gets drawn case by case, not by a single bright rule.
The Anti-Commandeering Rule
Even when the federal government has power to regulate something, it cannot force state officials to do the regulating. This is the anti-commandeering doctrine, and it comes directly out of the Tenth Amendment. Washington must use its own employees and resources to enforce its own laws.
The Supreme Court established the rule in New York v. United States (1992), striking down a federal provision that would have required states either to regulate radioactive waste on federal terms or to take ownership of it. Congress, the Court held, may not order states to enact or administer a federal program.7Legal Information Institute (LII) / Cornell Law School. Anti-Commandeering Doctrine
Five years later, Printz v. United States (1997) extended the principle to individual state officers. The Brady Handgun Violence Protection Act required local law enforcement to run background checks on gun buyers, and the Court ruled that Congress could not conscript state officers into a federal regulatory program.7Legal Information Institute (LII) / Cornell Law School. Anti-Commandeering Doctrine The federal government had to build its own background-check system.
The doctrine reached further in Murphy v. National Collegiate Athletic Association (2018). A federal statute called PASPA had prohibited states from authorizing sports betting. The Court struck it down, reasoning that telling a state it cannot pass a particular law commandeers the state legislature just as surely as telling it that it must.8Supreme Court of the United States. Murphy v. National Collegiate Athletic Association States moved quickly afterward to legalize and regulate sports gambling on their own terms.
The rule also keeps political accountability visible. When federal officials enforce federal policy, voters know whom to hold responsible. Shifting enforcement duties onto state workers would blur that line.
Spending Conditions: The Workaround and Its Limits
Congress cannot order states to adopt policies, but it can offer money with strings attached. Federal highway funds, education grants, and healthcare programs routinely come with conditions that shape state behavior, and the Supreme Court has permitted the practice within limits.
In South Dakota v. Dole (1987), the Court upheld a federal law that withheld a small share of highway funds from states allowing people under 21 to buy alcohol. Spending conditions, the Court said, must promote the general welfare, be stated clearly, relate to a legitimate federal interest, and not require anything independently unconstitutional. Financial pressure also cannot become so heavy that it crosses from encouragement into coercion.9Justia U.S. Supreme Court Center. South Dakota v. Dole
That coercion limit became real in National Federation of Independent Business v. Sebelius (2012). The Affordable Care Act expanded Medicaid eligibility and threatened to strip all existing Medicaid funding, not just the new expansion money, from states that refused to participate. The Court ruled this was unconstitutionally coercive because states had built their healthcare systems around existing Medicaid dollars and could not realistically walk away.10Justia U.S. Supreme Court Center. National Federation of Independent Business v. Sebelius States had to be allowed to decline the expansion without losing funding they already relied on.
“Or to the People”
The Tenth Amendment does not only protect state governments. Its final phrase reinforces the idea that some authority is not held by any government at all. Political power originates with citizens, and government has only what the people have handed over through the constitutional process.
The Ninth Amendment makes a related point from a different angle: “The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.”11Library of Congress. U.S. Constitution – Ninth Amendment The Tenth divides governmental power between Washington and the states. The Ninth protects individual rights that are not listed in the text. Together they form a two-layered check: the Ninth stops the government from claiming that unlisted rights do not exist, and the Tenth stops the federal government from claiming powers it was never given.