A statute is a written law formally enacted by a legislature, such as the U.S. Congress or a state legislature. The definition of a statute rests on how it comes into being: it starts as a bill, moves through a defined voting process in the legislative body, and becomes binding law once the executive signs it or a veto is overridden. Statutes are the primary source of law in most disputes and cover subjects ranging from tax rates and criminal penalties to civil rights and environmental standards.
How a Statute Differs from Other Kinds of Law
The American legal system pulls from several sources, and a statute is only one of them. Knowing what separates a statute from the others explains why it usually controls.
Statute vs. Case Law
Case law, sometimes called common law, comes from judges. When a court decides a dispute and issues a written opinion, that opinion can bind later courts in the same jurisdiction under the principle of stare decisis. A statute, by contrast, is written and voted on by elected legislators. When a statute addresses the same subject as a common-law rule, the statute generally controls. Courts still interpret what the statute means, but they cannot rewrite the text the legislature enacted.
Statute vs. Regulation
Federal agencies like the IRS and EPA issue regulations that carry legal force, but only because a statute authorized them. Congress passes a law setting broad policy and delegates the operational details to an agency. The agency’s rules, collected in the Code of Federal Regulations, must stay within the boundaries of the statute that created the rulemaking power. If a regulation exceeds or contradicts its authorizing statute, a court can strike it down.
Statute vs. Local Ordinance
Cities and counties pass ordinances that function like statutes at the local level, covering zoning, noise, business permits, and similar matters. An ordinance has real force inside that municipality’s borders, but it sits lower in the hierarchy than a state statute. If the two conflict, the state statute wins. State legislatures can also preempt entire subject areas, blocking local governments from legislating on those topics at all.
How a Statute Is Made
Every statute begins as a bill, a formal proposal for a new law or a change to an existing one.1USAGov. How Laws Are Made At the federal level, any member of Congress can introduce a bill. It is assigned to a committee that studies it, holds hearings, and may revise the text before deciding whether to send it forward. Most bills die in committee.
If the committee releases the bill, the full chamber debates and votes on it. Once one chamber passes the bill, it moves to the other, which runs its own committee review and vote. If the two chambers pass different versions, a conference committee reconciles the differences and sends a single final version back to both chambers.2house.gov. The Legislative Process
The approved bill then goes to the President, who has ten days (not counting Sundays) to act. The President can sign it, veto it and return it to Congress with objections, or do nothing. If the President takes no action while Congress remains in session, the bill becomes law after the ten-day window. If Congress adjourns before those ten days expire, the bill dies without a signature; that outcome is a pocket veto, and Congress cannot override it.3U.S. Government Publishing Office. House Practice: A Guide to the Rules, Precedents and Procedures of the House – Chapter 57 Veto of Bills A regular veto can be overridden, but only by a two-thirds vote in both chambers.1USAGov. How Laws Are Made
State legislatures follow the same basic pattern: introduction, committee review, a vote in each chamber (except Nebraska, which has only one), and the governor’s signature or veto. Congress’s authority to legislate comes from Article I of the U.S. Constitution, which vests “all legislative Powers” in the Senate and House.4Constitution Annotated. U.S. Constitution – Article I State legislatures draw their authority from their own state constitutions.
Public Laws and Private Laws
Once enacted, a federal statute is classified as either a public law or a private law based on who it affects. Most are public laws, which apply to the general population or a broad category of people across the jurisdiction and cover things like criminal conduct, tax obligations, and environmental standards.5GovInfo. Public and Private Laws
Private laws are much rarer. They target a specific individual, family, or small group, and often arise when someone has been harmed by a government program or is challenging an agency decision such as a deportation order.5GovInfo. Public and Private Laws Both types have full legal force, but a private law creates no general obligation on the public.
Where Statutes Sit When Laws Conflict
The Supremacy Clause in Article VI of the U.S. Constitution declares that federal law is “the supreme Law of the Land” and that state judges are bound by it despite anything in state law that says otherwise.6Constitution Annotated. Article VI – Clause 2 When a valid federal statute conflicts with a state statute, the federal law controls, and the state law is unenforceable to the extent of the conflict.
This is the basis of federal preemption. Sometimes Congress says outright that a federal statute overrides state law on a subject. Other times preemption is implied, either because the federal scheme is so comprehensive that no room is left for state rules or because complying with both laws at once is impossible. Preemption is not automatic, though. Most criminal law, family law, and property law remain the domain of state statutes.
Courts also have the power to invalidate a statute entirely if it violates the Constitution. This authority, known as judicial review, was established by the Supreme Court in the 1803 case Marbury v. Madison.7Constitution Annotated. Marbury v. Madison and Judicial Review When a court strikes down a statute as unconstitutional, that statute becomes unenforceable. The legislature can respond by passing a revised version that addresses the constitutional problem, but reenacting the same law and expecting a different outcome will not work.
Constitutional Limits on What a Statute Can Do
Legislatures have broad power to make law, but the Constitution draws hard lines. Article I, Section 9 states: “No Bill of Attainder or ex post facto Law shall be passed.”8Constitution Annotated. Overview of Ex Post Facto Laws Article I, Section 10 applies the same prohibition to the states.
An ex post facto law is one that retroactively changes the legal consequences of something you already did. In criminal law, that means neither Congress nor a state legislature can pass a statute that makes previously legal conduct a crime, increases the punishment for an offense after it was committed, or changes evidentiary rules to make conviction easier after the fact. The prohibition exists so people can rely on the law as it stands when they act.
A bill of attainder is a statute that declares a specific person or identifiable group guilty of a crime and imposes punishment without a trial. The Constitution forbids this because punishment is the job of the courts, not the legislature.
How to Find and Cite a Statute
When Congress passes a law, it enters the legal record chronologically in the Statutes at Large, which prints every public and private law as enacted. That chronological record is useful for historians but impractical for figuring out what current law says on a given topic. If three different Congresses amended the same tax rule over 20 years, the relevant pieces would sit in three different volumes.
Codification solves this. It reorganizes all currently effective statutes by subject matter into a single searchable collection.9Office of the Law Revision Counsel. Positive Law Codification The United States Code is the result. It divides federal statutory law into 54 broad titles. Title 26, for instance, is the Internal Revenue Code. Title 42 covers public health and welfare, including Social Security. Each title is subdivided into chapters, sections, and smaller units.10Office of the Law Revision Counsel. Detailed Guide to the United States Code Content and Features
A standard citation tells you where to look. “18 U.S.C. § 3571” means Title 18 of the United States Code, Section 3571. If you know a law only by its popular name, like the “Patriot Act” or the “Clean Air Act,” the U.S. Code includes a Popular Name Table that cross-references common names to their formal title and section numbers. Annual cumulative supplements keep the text current between full editions.11Govinfo. About the United States Code
The Code does not include treaties, agency regulations, or state laws. Agency regulations are collected separately in the Code of Federal Regulations, and each state maintains its own statutory code organized on similar principles.
What a Statute Can Impose
Statutes do three basic things: they require conduct, prohibit conduct, or establish government policy. The consequences of violating one depend on the statute itself and the classification of the offense. At the federal level, criminal offenses are grouped into classes based on the maximum prison term they carry, from infractions with five days or less of jail time up to Class A felonies punishable by life imprisonment.12Office of the Law Revision Counsel. 18 U.S. Code 3559 – Sentencing Classification of Offenses
Fines follow their own scale. An individual convicted of a federal felony faces a maximum fine of $250,000; organizations can be fined up to $500,000. If the offense involved financial gain or caused financial loss, the fine can climb to twice the gross gain or twice the gross loss, whichever is greater.13Office of the Law Revision Counsel. 18 U.S. Code 3571 – Sentence of Fine Those are federal figures. States set their own penalty ranges, and they vary widely.
Not every statute is criminal. Civil statutes create obligations enforced through lawsuits rather than prosecution. A civil statute might give you the right to sue an employer for discrimination, require a company to disclose information to consumers, or set the rules for forming a business. The consequences for violating one are usually monetary damages or court orders, not jail time.
How a Statute Is Changed or Repealed
A statute stays in force until the legislature that enacted it changes or removes it. Amending a statute follows essentially the same process as creating one: a bill proposing the change must pass both chambers and receive the executive’s signature or survive a veto override. The amended text then replaces the old language in the code.
Outright repeal works the same way, with the new law expressly rescinding the old one. Occasionally a newer statute conflicts with an older one without saying so. Courts call this implied repeal and strongly disfavor it. Generally, they will find an implied repeal only when the two statutes are irreconcilable, meaning there is no way to apply both at once. If any plausible reading lets both coexist, courts will take it.
Constitutional amendments can also override statutes. The Eighteenth Amendment established Prohibition, and the Twenty-First repealed it, rendering the underlying enforcement statutes moot. That is the most dramatic way a statute ends, and it is exceedingly rare.