Federal law in the United States is made by three branches working in defined roles: Congress writes statutes, the President signs or vetoes them and issues executive orders, federal agencies issue regulations under authority Congress has delegated, and federal courts interpret all of it and can strike down anything that conflicts with the Constitution. Treaties ratified by the Senate add a fourth source. So the short answer to who makes federal law is that no single branch does it alone, and the Constitution sets the order in which their work takes precedence.
Which Federal Law Wins When They Conflict
Not every federal rule carries the same weight. The U.S. Constitution sits at the top, and any statute, regulation, or executive action that conflicts with it is invalid. Federal statutes enacted by Congress and ratified treaties occupy the next tier. Agency regulations, which fill in the operational details, rank below the statutes that authorize them. If a regulation conflicts with its underlying statute, the statute controls.
Article VI, the Supremacy Clause, makes the Constitution, federal statutes, and treaties “the supreme Law of the Land,” binding on every state judge regardless of anything in state law to the contrary.1Congress.gov. U.S. Constitution Article VI A valid federal law overrides a conflicting state law, and the same is true of federal regulations when the issuing agency is acting within authority Congress properly delegated.
Congress Writes the Statutes
The Constitution vests “all legislative Powers” in Congress, making it the only body that can enact federal statutes.2Cornell Law School. U.S. Constitution Article I Congress has two chambers: the House of Representatives, with 435 voting members allocated by state population, and the Senate, with two senators from each state. Both chambers must pass identical text before a bill can go to the President.
The path is familiar in outline. A member introduces a bill, a committee studies and may revise it, the full chamber debates and votes, and when the House and Senate pass different versions, a conference committee works out a single text that both chambers then approve.3U.S. Senate. Frequently Asked Questions About Committees A simple majority is enough to pass most measures.
Congress also polices how the executive branch carries out the statutes it passes. The Supreme Court has recognized an implied oversight and investigation power under Article I, including the authority to compel testimony by subpoena, on the reasoning that informed legislation requires the ability to investigate.4Cornell Law School. Overview of Investigation and Oversight Power of Congress Those investigations must serve a legitimate legislative purpose, but they can reach broadly into agency spending, enforcement, and program management.
The President Signs, Vetoes, and Directs
Once both chambers pass a bill, it goes to the President under the Presentment Clause of Article I, Section 7. The President has ten days (Sundays excluded) to sign it, veto it, or do nothing. Signing turns the bill into a statute immediately. A veto returns the bill to Congress with written objections, and Congress can override only with a two-thirds vote in each chamber.5Congress.gov. Constitution Annotated Article I Section 7 Clause 2
Doing nothing cuts two ways. If Congress is still in session when the ten days expire, the bill becomes law without a signature. If Congress has adjourned during that window, the bill dies in what is known as a pocket veto, and there is no veto message for Congress to override.5Congress.gov. Constitution Annotated Article I Section 7 Clause 2
Executive Orders
The President also shapes federal policy through executive orders, which are written directives to federal agencies on how to carry out existing law and manage government operations. Executive orders do not pass through Congress. Their authority comes from Article II, which vests executive power in the President and requires the President to “take Care that the Laws be faithfully executed,” and from powers Congress has delegated by statute. An order that contradicts a statute or the Constitution can be struck down in court.
Emergency Declarations
Under the National Emergencies Act, a presidential declaration activates special powers scattered across dozens of statutes, which can include sanctions, redirecting military funds, or trade restrictions. Each declaration expires after one year unless the President publishes a renewal notice in the Federal Register at least 90 days before the anniversary. Congress can end an emergency by joint resolution, though that resolution still requires the President’s signature or a veto override.6Office of the Law Revision Counsel. 50 USC 1622 National Emergencies
Federal Agencies Write the Regulations
Much of the federal rulebook you actually live with was written not by Congress but by agencies. Congress often passes a broad statute and then delegates the technical details to a specialized agency such as the Environmental Protection Agency, the Securities and Exchange Commission, or the Federal Aviation Administration. The regulations these agencies issue carry the force of law and bind individuals and businesses just as statutes do.
Notice and Comment
The Administrative Procedure Act governs how agencies make rules.7Office of the Law Revision Counsel. 5 USC 551 Definitions An agency normally publishes a proposed rule in the Federal Register with an explanation of what it would do and why.8Office of the Law Revision Counsel. 5 USC Part I Chapter 5 Subchapter II Administrative Procedure The public then gets a comment period. After reviewing comments, the agency issues a final rule with a statement of its reasoning. The APA allows agencies to skip the process in narrow circumstances, such as when delay would be impractical or contrary to the public interest, and courts scrutinize those exceptions closely.
Enforcement
Agencies enforce as well as write. Acting within its delegated authority, an agency can investigate potential violations, conduct hearings, and impose penalties, which may be substantial. Civil fines under the Clean Water Act, for example, reach up to $68,445 per day per violation after inflation adjustments.9Federal Register. Civil Monetary Penalty Inflation Adjustment
Courts Can Set Regulations Aside
Agency regulations are not final. Under the APA, anyone harmed by a regulation can challenge it in federal court, and a reviewing court can strike down an agency action that is arbitrary, exceeds statutory authority, violates the Constitution, or ignores required procedures.10Office of the Law Revision Counsel. 5 USC 706 Scope of Review
In 2024 the Supreme Court decided Loper Bright Enterprises v. Raimondo and overruled the longstanding Chevron doctrine. For roughly 40 years, courts had deferred to an agency’s reasonable interpretation whenever a statute was ambiguous. Under the new standard, courts use their own independent judgment to say what a statute means, even when the language is unclear. They may still look to an agency’s expertise and reasoning, but they cannot treat the agency’s interpretation as controlling simply because the statute is ambiguous.11Supreme Court of the United States. Loper Bright Enterprises v. Raimondo
Federal Courts Interpret and Can Strike Down
Article III vests “the judicial Power of the United States” in the Supreme Court and whatever lower courts Congress creates.12Congress.gov. Constitution Annotated Article III Section 1 Federal courts do not write statutes, but they shape federal law in two important ways: they interpret what statutes and the Constitution mean, and they can invalidate laws that violate the Constitution.
That second power, judicial review, was established by the Supreme Court in Marbury v. Madison in 1803. The Court held that the Constitution is the “superior paramount law” and that any statute conflicting with it “is not law.”13Cornell Law School. Marbury v. Madison and Judicial Review The principle applies to all federal courts, not just the Supreme Court.
When a federal court interprets a statute or a constitutional provision, that interpretation becomes case law. Under the doctrine of stare decisis, lower courts must follow it. A Supreme Court decision binds every federal court below it. A federal circuit court decision binds the district courts within that circuit. This vertical structure keeps the same statute from meaning different things in different places. Stare decisis is not absolute: the Supreme Court can overrule its own prior decisions, as it did with Chevron, when it concludes a precedent was seriously wrong or has become unworkable. Overrulings are rare, and most Supreme Court interpretations remain stable for decades.
Treaties and Executive Agreements
The Constitution lets the President negotiate treaties, but a treaty takes effect only if two-thirds of the senators present vote to approve it.14Congress.gov. Constitution Annotated Article II Section 2 Clause 2 Once ratified, a treaty is part of the “supreme Law of the Land” under Article VI and can override conflicting state law just as a federal statute would.1Congress.gov. U.S. Constitution Article VI The President still has the final call on whether to formally enter the treaty after the Senate consents.15Cornell Law School. Overview of Presidents Treaty-Making Power
Presidents also enter executive agreements with foreign nations without a two-thirds Senate vote. Some are grounded in an existing statute or prior treaty, and others rest on the President’s constitutional authority over foreign affairs. The Supreme Court has held that valid executive agreements can override conflicting state law, on the reasoning that foreign relations power sits with the national government.16Cornell Law School. Legal Effect of Executive Agreements Executive agreements based solely on presidential authority are generally considered less durable than ratified treaties, since a later president can revoke them without congressional approval.
Where to Read Federal Law Yourself
Each source of federal law has its own home. Knowing which to open saves time.
- United States Code (U.S.C.): the official collection of general and permanent federal statutes, organized into 54 titles by subject. Title 26 is the tax code; Title 42 covers public health. The Office of the Law Revision Counsel maintains a searchable version at uscode.house.gov.17Office of the Law Revision Counsel. Detailed Guide to the United States Code Content and Features
- Code of Federal Regulations (CFR): the codified version of agency regulations. The print edition updates annually, and the Electronic Code of Federal Regulations at ecfr.gov updates continuously, which is where you look to confirm current regulatory text.
- Federal Register: published every business day, this is where agencies announce proposed rules, final rules, and other official notices. A Federal Register notice will also tell you how to submit a public comment on a proposed rule and by when.
The pattern is clean. Congress writes laws that end up in the U.S. Code. Agencies write regulations that end up in the CFR. The Federal Register is where the rulemaking happens in public before it reaches either book.