Where the rules come from: constitutions, statutes, regulations, court decisions and contracts, how they rank, and how federal and state law fit together

Constitutions. A constitution sets up the government and limits what it may do. The United States Constitution binds the federal government and, through the Fourteenth Amendment, the states on many matters. Every state also has its own constitution. A constitution is the highest kind of law in its own sphere: a rule that conflicts with it can be struck down. Constitutions mostly protect against government, so they decide whether a police officer, a public school or a city acted lawfully, but they rarely decide a dispute between two private people.

Statutes. A statute is a law passed by a legislature: Congress for the nation, the state legislature for a state. Statutes are the main written rules for most everyday problems: landlord and tenant, employment, debt collection, consumer protection, family law and the criminal law. They are collected in codes, which are organised by subject. The words of the statute are the starting point, and the definitions and exceptions in it often decide the case.

Regulations. A statute often hands the details to an agency: a labour department, a housing agency, a consumer bureau. The agency writes regulations that have the force of law as long as they stay within what the statute allows. If you ask what exactly an employer must do or what a landlord must disclose, the answer is often in a regulation and not in the statute.

Court decisions. Courts do not only apply the law; they explain it. In the United States, a decision of a higher court on a legal question binds the lower courts in the same system, which is the principle of precedent. Some areas, such as much of contract law, property law and tort law (injuries and wrongs), grew mostly out of decisions over centuries, and the statutes in them often build on that case law. A decision is only as useful as it is relevant: it must come from a court whose decisions bind yours, be about a similar problem and still be good law.

Local ordinances. Cities, counties and towns pass ordinances on matters such as zoning, noise, building codes, parking, short-term rentals and rent rules. They rank below state law, but for a neighbour dispute or a parking ticket they are often the rule that matters most.

Contracts. The contract you signed is also a source of rules, for you and the other party. A lease, an employment agreement, a loan, a subscription and a set of terms and conditions all create binding duties, within the limits that the law sets. A contract cannot take away a right that a statute gives you and does not allow you to waive, but it fills in everything the law leaves open.

The ladder. When two sources conflict, the higher one wins. The US Constitution is at the top, then federal statutes and treaties, then federal regulations. A state constitution ranks above that state’s statutes, which rank above its regulations and above local ordinances. A contract sits at the bottom, because it must stay within all the rules above it. Courts interpret all of these, and their interpretation of a rule is part of what the rule means.

Federal and state. The country is divided between a federal government with listed powers and fifty states with broad general powers. Most of the law that touches your daily life is state law: landlord and tenant, most contracts, family law (divorce, custody, wills), most crimes, most employment protections beyond the basics, traffic, licensing and small claims. Federal law governs certain subjects across the country: immigration, bankruptcy, federal taxes, patents and copyright, many workplace and civil rights protections, the mail, and the federal crimes. Often both apply at once, and when they do, a valid federal law generally prevails over a conflicting state law, while a state may usually give more protection than the federal minimum.

• Ask who regulates the subject. A deposit dispute is usually state and local law. A claim about a debt collector’s calls may involve federal and state law. A visa is federal.
• Ask which state. The law of the state where the property is, where you work or where the event happened usually decides. A move between states can change the answer.
• Look for the floor and the ceiling. Federal law often sets a minimum, and a state may add more protection. A local rule may add more still, unless the state has forbidden it.

Civil matters are disputes between private parties (people, businesses) about rights and money: a deposit, a contract, an injury, a divorce. The person who sues is the plaintiff and the other is the defendant; the usual remedy is money or an order to do or stop doing something. Criminal matters are wrongs that the state prosecutes, in the name of the public: the prosecution is brought by the government, the possible outcome is a conviction, a fine, probation or jail, and the protections of the accused are strong. The same event can be both, such as an assault that is a crime and also a civil wrong for which the victim may sue.

Public and private law. A dispute with the government (a benefits decision, a permit, a tax assessment) is public or administrative law, with its own agencies and procedures. A dispute with another person or company is private law. Knowing which side of this line you are on tells you who decides, which is the subject of the next module.

• Who is the other side? A person or business means civil. The state or a city bringing a charge means criminal. An agency deciding on your benefit or permit means administrative.
• What can be the result? Money or an order is civil. A conviction or a penalty imposed by the state is criminal or regulatory.
• Who must prove it, and how well? The standard of proof differs between civil and criminal cases, as the module on proof explains.

Why this matters to you. Almost everything that this toolkit helps with is civil or administrative. If you are ever charged with a crime, or questioned by the police in a way that could lead to a charge, or your liberty, your children or your immigration status is at stake, you have reached a red flag: that is the moment to get a lawyer, and a public defender or a legal aid office is available to many people who cannot pay.