How a Bill Becomes a Law in Congress

Thousands of bills are introduced in each Congress. Only a small fraction become law. Here is the real path from an idea to a signed statute, including the filibuster and the veto.

Photo: Wikimedia Commons, via Wikimedia Commons (CC BY-SA)

The cartoon version of how a bill becomes a law, sung on Saturday mornings, is roughly right but leaves out the parts where most bills quietly die. Here is the fuller picture of how legislation actually moves through Congress.

Introduction and committee

A bill is introduced by a member of the House or the Senate and given a number (H.R. for House bills, S. for Senate bills). One constitutional wrinkle: bills that raise revenue must originate in the House.

The bill is then referred to the relevant committee, and this is where most legislation stops. Committees hold hearings, rewrite the text in a process called markup, and vote on whether to send it to the full chamber. A bill that never gets a committee vote simply never advances.

Floor debate and the two-chamber rule

If a committee reports the bill out, it goes to the floor for debate and a vote. In the House, the Rules Committee typically sets the terms of debate, and passage needs a simple majority.

Here is the catch that trips up a lot of people: both chambers must pass identical text. A bill that passes the House still has to clear the Senate in the same form before it can go to the president.

The Senate filibuster

The Senate has a feature the House does not: the filibuster. Most legislation can be debated indefinitely, and ending debate requires a cloture vote of three-fifths of the Senate, 60 votes when there are no vacancies. In practice, that turns 60 into the real threshold for passing most bills, not 51.

There is a major workaround. Certain budget-related bills can move under reconciliation, which limits debate and cannot be filibustered, so it passes with a simple majority. But reconciliation is constrained by the Byrd Rule, which strips out provisions that do not have a real budgetary effect. That is why big policy packages are often reshaped to fit, or fail to fit, the reconciliation mold.

Reconciling the two versions

When the House and Senate pass different versions of the same bill, the differences have to be worked out, either through a conference committee or by the chambers amending each other's bills back and forth. Both chambers then have to approve the same final text.

The president's turn

Once a bill reaches the president, there are a few outcomes:

• Sign it, and it becomes law.
• Veto it, sending it back to Congress with objections.
• Do nothing. If Congress is in session, the bill becomes law after 10 days without a signature. If Congress adjourns during that window and the president has not signed, the bill dies by pocket veto.

Congress can override a regular veto, but the bar is high: two-thirds of both chambers. A pocket veto cannot be overridden at all.

Most bills never make it

The attrition is dramatic. Across recent decades, only a small single-digit percentage of introduced bills become law, and many that do are ceremonial or administrative, naming a post office, for example. The exact rate varies by Congress and by how you count, but the headline holds: introducing a bill is easy, and enacting one is hard.

Passing a law in the US is designed to be difficult. The many veto points are a feature, not a bug, and they explain why major legislation is rare and hard-fought.

Understanding this path is the key to reading the news about Congress. When a bill "passes the House," that is often just the first of several hurdles, not the finish line.