Primary Law Explained for People Who Do Not Read Statutes

Short answer: primary law is the law itself, the actual text a government body issued. It covers constitutions, statutes (laws passed by a legislature), regulations (rules written by government agencies), court rules, agency guidance and court decisions. Secondary sources are writing about the law, such as textbooks, articles and blog posts. When someone tells you what the law says, the primary text is where you check them.

TL;DR

• Primary law is the text a government body issued. A secondary source only describes it.
• Court decisions are primary law. Judges help set the law, so they are part of it.
• The rough order of power is constitution, then statute, then regulation, then guidance. Courts referee all of it.
• Binding means a court must follow a source. Persuasive means a court may weigh it and may set it aside.
• Before you rely on any text, check that it is official, current, from the right government and the right kind.

What counts as primary law, and what does not

Picture a company rulebook. The rulebook itself is primary. A manager's email explaining the rulebook is secondary. It may be accurate, but nobody can be held to it.

Secondary sources include treatises (books that explain an area of law), law review articles, news stories, blog posts and chatbot answers. They help you understand. They cannot replace the text they describe. Our guide to the types of primary law in the US counts eight kinds. They include treaties (deals between governments), executive orders (written orders from a president or governor) and ordinances (local laws). This post is the short tour of the six you will meet most often.

One subject, six kinds of law

Take a question every employer meets: how many hours can someone work before the pay rate changes? Every kind of primary law touches it.

Constitution. This is the founding document that creates a government and limits it. Article I, Section 8 of the US Constitution gives Congress the power "To regulate Commerce with foreign Nations, and among the several States, and with the Indian Tribes." Federal wage law rests on that power. Article VI adds that the Constitution and the federal laws made under it are "the supreme Law of the Land." Find the federal text at constitution.congress.gov.

Statute. Congress used that commerce power to pass the Fair Labor Standards Act. The act is sorted by subject into the United States Code, so it appears as 29 U.S.C. § 207(a)(1), meaning Title 29, section 207. That section bars an employer from working someone "for a workweek longer than forty hours" unless the extra hours are paid "at a rate not less than one and one-half times the regular rate." Read it on the official US Code site. The act and the code can differ, as our session law guide shows.

Regulation. The Department of Labor wrote rules to carry out that statute. They sit in Title 29 of the Code of Federal Regulations, the book of federal agency rules. Section 778.101 says 40 hours is the most an employee may work in a workweek "without receiving additional compensation at not less than the statutory rate for overtime." It calls the statute "section 7(a) of the Act." The code prints the same provision as § 207(a). See the rule on the electronic Code of Federal Regulations, called the eCFR. See our guide to regulations versus statutes.

Court rule. Courts write rules for how a case runs. Rule 12(a)(1)(A)(i) of the Federal Rules of Civil Procedure says a defendant must serve an answer "within 21 days after being served with the summons and complaint." The complaint is the paper that starts a lawsuit, the summons is the notice to appear, and the answer is the reply. "Served" means formally delivered. So if a worker sues over unpaid overtime in federal court, a 21-day clock starts. The Supreme Court adopts these rules, and Congress can block them. The federal courts publish them at uscourts.gov.

Agency guidance. Agencies also explain their rules in fact sheets, manuals and letters. The Department of Labor's Fact Sheet #23, revised October 2019, opens: "An employer who requires or permits an employee to work overtime is generally required to pay the employee premium pay for such overtime work." It shows how the agency reads the law. It is a summary. The regulation controls.

Court decision. A judge or panel settles a dispute and writes down the reasons. In Encino Motorcars, LLC v. Navarro, 584 U.S. 79 (2018), the Court's own summary says car dealership service advisors "are exempt from the Fair Labor Standards Act's overtime-pay requirement." ("584 U.S. 79" means volume 584 of the official Supreme Court reports, page 79.) Lower courts must follow that ruling. The Court posts its rulings at supremecourt.gov.

The map in one table

How the pieces rank

The constitution sits at the top. A statute that breaks it can be struck down. A regulation sits under its statute and has force only inside the power that statute gave. Guidance sits under the regulation.

Court decisions do not fit on the ladder. They act as the referee. Judges say what a statute means. They can strike down a statute that breaks the constitution, and a regulation that goes past its statute. Federal law also wins over a conflicting state law, which is what Article VI of the Constitution says. Each state repeats the same stack.

Binding or persuasive

Primary does not always mean binding. A source is binding when a court must follow it. It is persuasive when a court may read it, weigh it and still go the other way.

An attorney general opinion shows the difference. Washington's Attorney General issued Attorney General Opinion 2025 No. 3 on September 18, 2025, at a legislator's request. The question was: "May a municipality use lodging tax revenues to repay revenue bonds for affordable workforce housing within one-half mile of a transit station?" A municipality is a city or town government. Revenue bonds are debt it repays from a set income. The answer was yes, under RCW 67.28.160, a section of the Revised Code of Washington, the state's statutes. The office's opinions page says formal opinions are "not binding on the courts, but they are usually given careful consideration and respect." A city finance team would read it closely. A judge could still disagree. See attorney general opinions by state for other states.

Court decisions split the same way. A Supreme Court ruling on federal law binds every lower court. A decision from another state's court only persuades yours.

What goes wrong

• You read a summary and treat it as the rule. Fact sheets, blog posts and chatbot answers are not the text.
• You stop at the statute. The regulation often holds the numbers and the deadlines.
• You cite a decision from the wrong court. It exists, and it may bind nobody in your case.
• You use an old or unofficial copy. Many sites copy the law, and some lag behind.
• You mix up governments. Federal text says nothing about your state's extra rules.

Questions to ask before you rely on a text

Who published it? Look for a government site, not a copy. How old is it? Find the date, and the line that shows the last change. What kind is it? A statute, a regulation, a rule, guidance and a decision carry different weight. Whose is it? Federal text and each state's text answer different questions. Where does it bind? Ask whether the court in your case must follow it or may only consider it.

Then write down exactly what you relied on. Our guide to citing a statute or regulation shows how. Buying legal data? Start with what legal data is and the ten questions to ask a vendor. If your question spans many states, see how to run a 50-state survey.

This is general information, not legal advice.

This guide is part of US Law Data: The Complete Guide, a map of where US law comes from and how to use it.

FAQ

What is primary law in simple terms? Primary law is the law itself: the text a government body issued. Writing about the law, like a textbook or a blog post, is secondary.

What is the difference between primary and secondary legal sources? A primary source is the law. A secondary source explains it. You can cite a secondary source to help a reader understand, but only primary law can bind a court.

What is primary authority? It is primary law you rely on to support a legal point. It is binding if the court must follow it and persuasive if the court may. That depends on the court and the place.

Is case law primary law? Yes. In US practice, a court decision is primary law. Judges' rulings often tell you what a statute means.

Does primary law always have to be followed? No. A constitution, a statute and a regulation within its limits bind you where they apply. An attorney general opinion or an out-of-state decision may only persuade. Check who issued it and where it applies.

For the statute and regulation text behind guides like this one, see the Vaquill AI legal data API, which lets software pull that text.

Priyansh Khodiyar

Co-Founder & CTO

Priyansh leads engineering and AI at Vaquill AI: the pipelines that pull statutes, regulations and court rules from every US jurisdiction's official publisher, and the REST API, MCP server and open dataset that serve them.