The Constitution's instructions for making a law fit in a few sentences of Article I: a bill must pass both the House and the Senate and be presented to the President. Everything else, from committees and floor schedules to filibusters and conference negotiations, has been built on top of that requirement by two centuries of rules, precedents, and political practice.
This guide follows a bill from introduction to enactment. Each stage links to a full entry, so you can read straight through for the big picture or stop at any step for the details.
Committees are where most legislative work happens and where most bills end. A committee chair decides whether to hold hearings and a markup, the session in which members debate and amend the text line by line. Nonpartisan staff at the Congressional Budget Office estimate costs, and the Congressional Research Service supplies analysis. A bill that a committee approves is reported to the full chamber, often with a written report explaining it.
The House and Senate must pass exactly the same text. When their versions differ, the chambers either trade amendments back and forth or, less often today, appoint a conference committee to negotiate a compromise that both must approve. Large packages, such as omnibus spending bills, often bundle many measures together, and amendments called riders can carry unrelated policy changes on must-pass legislation.
Any senator or representative can introduce a bill, and only they can. The ideas behind bills come from everywhere: the President's agenda and budget, federal agencies, state and local officials, advocacy groups and industries, and constituents. A bill gets a number, H.R. or S. followed by digits, and the presiding officer refers it to the committee with jurisdiction. Some measures are resolutions rather than bills, and only joint resolutions carry the force of law.
The Senate works differently. Much of its business moves by unanimous consent, so any single senator can slow things down, and senators can place holds on bills and nominations. Debate is unlimited unless 60 senators vote to end it through cloture, which is why most significant legislation needs 60 votes. Budget reconciliation bills are the main exception, passing by simple majority within limits set by the Byrd rule. The majority has also used the nuclear option to lower thresholds for nominations.
In the House, the majority controls the floor. The Speaker and majority leadership decide what comes up, and the Rules Committee writes a special rule for each major bill setting how long debate lasts and which amendments, if any, may be offered. Many minor bills pass quickly under a suspension procedure that requires a two-thirds vote. A majority of members can force a vote on a bill leadership is blocking by signing a discharge petition, though this rarely succeeds.
Once enrolled, a bill goes to the President, who has ten days, excluding Sundays, to act. A signed bill becomes law, and an unsigned bill becomes law automatically if Congress is in session. If Congress has adjourned and the President does not sign, the bill dies by pocket veto. A regular veto returns the bill to Congress, which can override it with two-thirds of both chambers. Presidents sometimes issue signing statements describing how they will interpret the new law. Enacted bills are numbered as public laws and folded into the U.S. Code.
Passing a law is only the beginning. Agencies turn statutes into detailed rules, courts interpret them, and Congress funds them each year. For what happens next, see the guides on how federal regulations are made and how the federal budget works, or step back to the three branches.