How does a bill become a law? Every new law starts out as an idea. A bill is a plan for a new law, or a change to an old law. Congress is the part of the national government that makes laws, and Congress has two parts: the House of Representatives and the Senate. Let's follow a bill through committees, debates and votes, then past the president's desk, and then look at courts, states and the United Kingdom.

Now go back to 1787. In 1787 the convention met in the Pennsylvania State House in Philadelphia, ostensibly to amend the Articles of Confederation. Leaders called the Framers wrote the U.S. Constitution there. Britannica says the Connecticut Compromise was offered by Roger Sherman and Oliver Ellsworth at the 1787 convention to solve the dispute between small and large states over representation. The Great Compromise is also called the Connecticut Compromise. It provided a dual system of congressional representation. The Great Compromise gave each state equal seats in the Senate and seats in the House based on population.

Every bill needs a starting point. People can ask their lawmakers to start a new law, and a bill can be started by a member of the House or Senate. There is one rule about money. Only the House of Representatives can start a bill about taxes or raising money, although the Senate can still make changes to it. After a bill is introduced, the next stop is a committee.

After a bill is introduced, it goes to a committee of lawmakers who study it and can change it. Each house of Congress has standing (permanent) committees and select (special and temporary) committees. House committees often begin with a public hearing, where members hear witnesses who represent different viewpoints on the bill. After hearings, a House committee holds a "mark-up" session. Members study the viewpoints, may offer amendments, and vote to accept or reject the changes.

When the mark-up ends, the committee has choices. A House committee can report a bill, with or without amendments, or table it, which means no further action on it will happen. A House committee may report a new "clean bill" that includes all the amendments it approved. The clean bill gets a new number. When a House committee votes to report a bill, it writes a Committee Report that describes the purpose and scope of the bill and the reasons for recommending approval.

After a committee releases a bill, the bill is put on a calendar to be voted on, debated or amended. In the House, debate on a bill may be governed by a "rule", which is itself a simple resolution that the House must pass. A rule sets out the particulars of debate for a specific bill. Debate time on a House bill is normally divided between supporters and opponents. In the House, members debate amendments to a bill and then vote on them.

When the House passes a bill, it goes to the Senate, which studies and votes on it too. If the Senate changes a bill, the House has to look at the changes. The two sides must work out their differences. If the Senate and House pass different versions, a conference committee of members from both can settle the differences and report one identical bill back for a vote in each house. After both houses pass a bill in identical form, it is called "enrolled" and is sent to the president.

The president has several choices. The president may sign an enrolled bill into law, veto it and return it to Congress, let it become law without a signature, or at the end of a session pocket-veto it. The Government Publishing Office prints the revised bill in a process called enrolling. The president then has 10 days to sign or veto the enrolled bill. In a regular veto, the president returns the unsigned bill to the house of Congress where it began, within 10 days, usually with a memorandum of disapproval or a veto message.

A veto does not always end a bill. To override a veto, Congress needs a two-thirds vote in each house. A pocket veto cannot be overridden by Congress. The Constitution gives the president 10 days, not counting Sundays, to act on a bill. George Washington issued the first regular veto on April 5, 1792. The first time Congress overrode a veto was March 3, 1845, when it overrode John Tyler's veto of S. 66. After the president signs a bill into law, it goes to the Office of the Federal Register, which assigns a law number and prepares it for publication as a slip law.

Next, look at the courts. The U.S. government has three branches: legislative, executive and judicial. The system of checks and balances lets each branch respond to the actions of the others. The Supreme Court can overturn laws that go against the Constitution. In Marbury v. Madison, outgoing President John Adams had issued William Marbury a commission as justice of the peace, but the new Secretary of State, James Madison, refused to deliver it. Marbury sued to obtain it. With his decision in Marbury v. Madison, Chief Justice John Marshall established the principle of judicial review. Judicial review is the power of the courts to examine the actions of the legislative, executive and administrative arms of government and decide whether they are consistent with the constitution.

Next, look at one state. In California, a bill starts when a person or group persuades a member of the Legislature to author it. The Legislative Counsel's Office then drafts it into the actual bill. Local ordinances often follow set steps: public notice, a public hearing, a required number of votes, and publication of the final ordinance. An agency cannot issue a rule unless a law gives it the authority to do so.

Other countries use other methods. In the United Kingdom, Parliament makes the laws. A bill must be approved by both the House of Commons and the House of Lords before it becomes an Act of Parliament. As of November 2026, a bill agreed by Parliament has to be approved by the King before it becomes law. An Act of Parliament creates a new law or changes an existing law.

Words to know

• amendments: added changes
• enrolled: passed by both
• ordinance: local law
• judicial: court-related
• Parliament: UK lawmakers