The Tenth Amendment says that any power the Constitution does not give to the federal government, and does not forbid to the states, stays with the states or with the people. That one sentence, ratified in 1791 as the closing entry of the Bill of Rights, is the structural rule that keeps the federal government to its listed powers and leaves everything else to state governments or to individual citizens.
The Exact Text
The amendment reads: “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.”1Constitution Annotated. Tenth Amendment
Three ideas sit inside that sentence. The federal government has only the powers the Constitution specifically hands it. States keep everything else, unless the Constitution explicitly takes a power away from them. And some authority belongs to neither level of government at all, remaining with ordinary citizens.
The amendment doesn’t create new rights or hand out new powers. It confirms a default: when in doubt about who has authority over some question, the answer is not automatically Washington.
What “Reserved to the States” Actually Covers
The word “reserved” is doing real work. States existed as independent political entities before the Constitution was written, and they entered the Union keeping every power they didn’t expressly give up. The federal government doesn’t grant states their authority; states have it inherently. That’s why the default in any power dispute leans toward the states rather than the national government.
The largest category of reserved power is what courts call the “police power,” which is broader than law enforcement. It refers to a state’s general authority to protect the health, safety, and welfare of its residents. In everyday terms, that means:
- Public schools, curriculum standards, and local school funding.
- Licensing for doctors, lawyers, engineers, and dozens of other professions, with each state setting its own education requirements, exams, and fees.
- Building codes, fire regulations, speed limits, quarantine orders, and vaccination requirements.
- Election administration, ballot design, and most of the procedural rules that govern voting.
- Business activity happening entirely within a state’s borders.
This is why policy can look so different from one state to the next. A public health approach that fits a rural state might not fit a densely populated one. The Tenth Amendment is what makes that variation possible instead of requiring a single national rule for every question.
“Or to the People”
The closing phrase does more than round out the sentence. Government power is not a two-way toggle between federal and state; some authority was never given to any government and stays with individual citizens. The amendment doesn’t list what those retained rights are, and that silence is deliberate. The framers didn’t want any catalog of rights read as complete, which is also why the Ninth Amendment sits alongside the Tenth. Together, the two amendments create a constitutional presumption that people hold more freedom than any document could spell out.
How the Amendment Limits Federal Power
The Tenth Amendment only makes sense read against the powers the Constitution does grant. Those are listed mainly in Article I, Section 8: the authority to tax, borrow, regulate interstate and foreign commerce, coin money, establish post offices, declare war, raise armies, and about a dozen other specific functions.2Constitution Annotated. Article I Section 8 A federal action has to trace back to one of those grants. If it can’t, the Tenth Amendment says the federal government has overstepped.
That picture gets more complicated because of the final clause of Article I, Section 8, which lets Congress make all laws “necessary and proper” for carrying out its listed powers. In McCulloch v. Maryland (1819), Chief Justice John Marshall read “necessary” broadly, treating it as “conducive to” or “useful for” rather than “absolutely indispensable.”3Constitution Annotated. Necessary and Proper Clause Early Doctrine and McCulloch v Maryland That interpretation gave Congress room to pass laws that aren’t explicitly listed, as long as they serve a legitimate constitutional purpose.
The Commerce Clause Boundary
The biggest source of tension with the Tenth Amendment has been the Commerce Clause, which lets Congress regulate commerce “among the several States.” For much of the twentieth century, the Supreme Court read that power expansively, allowing federal regulation of activities with even a loose connection to interstate commerce. During that era the Tenth Amendment seemed close to a dead letter.
In 1995, United States v. Lopez changed that. The Court struck down the Gun-Free School Zones Act, holding that possessing a firearm near a school was a noneconomic activity with no substantial effect on interstate commerce and that Congress had shown no real link between the two.4Justia. United States v Lopez Accepting the government’s chain of reasoning, the majority warned, would let Congress regulate essentially anything and erase the line between federal and state authority. Lopez reestablished that the Commerce Clause has outer limits.
The Anti-Commandeering Doctrine
One of the most practical consequences of the Tenth Amendment is a rule the Supreme Court has built from it: the federal government cannot force state officials to carry out federal programs. Courts call this the anti-commandeering doctrine.
It first appeared in New York v. United States (1992). Congress had tried to deal with radioactive waste by giving states a “choice”: regulate waste according to federal instructions, or take ownership of all the waste and accept liability for it. The Court called that no choice at all. Both options amounted to Congress ordering a state legislature to implement a federal program, which the Constitution does not permit.5Legal Information Institute. New York v United States Congress can regulate people and businesses directly through federal agencies, but it cannot commandeer state governments to do federal work.
Five years later, Printz v. United States extended the rule to state executive officials. The Brady Act had required local law enforcement officers to run background checks on handgun buyers. The Court struck that requirement down, holding that Congress cannot conscript state officers to administer a federal program, even temporarily.6Legal Information Institute. Anti-Commandeering Doctrine Congress remained free to set up its own background-check system, and it did, but it could not draft state employees to run it.
The doctrine’s most recent high-profile application came in Murphy v. National Collegiate Athletic Association (2018), where the Court struck down a federal law that barred states from authorizing sports gambling. The problem was that Congress told state legislatures they could not change their own laws on the subject. Congress cannot issue orders to state legislatures to keep or repeal state-level rules. That ruling opened the door for states to legalize sports betting on their own terms.
The Supremacy Clause Boundary
The Tenth Amendment does not mean states can simply ignore federal law. Article VI of the Constitution, the Supremacy Clause, establishes that the Constitution and federal laws made under it are the “supreme Law of the Land,” and state judges are bound by them even when state law says otherwise.7Constitution Annotated. Overview of Supremacy Clause When a valid federal law directly conflicts with a state law, federal law wins. The question is always whether the federal law is actually valid, meaning traceable to a constitutional grant of power.
Federal preemption comes in several forms. Sometimes Congress writes it into the statute, stating outright that federal law overrides state law on a topic. Sometimes preemption is implied because federal regulation is so thorough that no room is left for state rules, or because a state law directly contradicts what federal law requires. The Supreme Court generally presumes Congress did not intend to displace state law unless that intent is clear.7Constitution Annotated. Overview of Supremacy Clause That presumption acts as a practical shield for state authority when the situation is ambiguous.
Spending Power and the Line Into Coercion
Even where Congress can’t regulate the states directly, it has a powerful indirect tool: money. Congress can attach conditions to federal grants, effectively telling states they’ll get funding if they adopt certain policies. Most of the time that arrangement is constitutional, because states are free to turn down the money and ignore the conditions. But the Supreme Court has recognized that at some point the financial pressure becomes so intense that the “choice” is illusory.
That line was drawn in NFIB v. Sebelius (2012), the Affordable Care Act case. Congress had required states to expand Medicaid eligibility or lose all of their existing Medicaid funding. Chief Justice Roberts concluded that threatening to withhold funds worth roughly ten percent of an average state’s entire budget amounted to “a gun to the head,” crossing from persuasion into unconstitutional coercion.8Congressional Research Service. Medicaid and Federal Grant Conditions After NFIB v Sebelius The ruling made the Medicaid expansion optional. The Court did not specify exactly where below ten percent the coercion line falls, which is why future spending-condition disputes continue to be litigated case by case.
Where the Tenth Amendment Shows Up Today
The amendment sits at the center of several ongoing policy fights. State marijuana legalization is the most visible. Marijuana remains illegal under federal law, yet a majority of states have legalized it in some form. Because the anti-commandeering doctrine bars the federal government from forcing state police to enforce federal drug laws, these state regimes operate in a legal gray zone where state and federal law directly contradict each other.
Sanctuary policies raise the same principle. When local governments decline to help federal immigration authorities detain or identify undocumented residents, they’re relying on the rule that the federal government can enforce its own immigration laws with its own agents but cannot draft local police to do it. States and cities have also invoked Tenth Amendment arguments against federal executive policies on climate regulation, vaccine mandates, and border enforcement.
After the Supreme Court overturned Roe v. Wade in 2022, abortion policy returned to the states, producing a patchwork of laws ranging from near-total bans to explicit protections. Some states have proposed laws targeting residents who travel to other states for abortion care, raising new questions about how far one state’s police power reaches and where it collides with another state’s sovereignty.
These conflicts are the Tenth Amendment doing what it was written to do: forcing an ongoing negotiation between centralized authority and local control, and making sure the federal government can’t quietly absorb powers it was never given.