A bill becomes a U.S. law by starting as an idea, getting sponsored in Congress, passing through committees for review, debate, and voting in both the House and Senate (in identical forms), and finally being signed by the President, or having a presidential veto overridden by a two-thirds vote in both chambers. If the President takes no action for 10 days while Congress is in session, the bill becomes law automatically, but if Congress adjourns within that time and the President doesn’t sign, it’s a “pocket veto”.
Step 1: An idea becomes a bill
A bill starts as a proposal to create a new law or change an existing one. The idea can come from a member of Congress, from a campaign promise, or from people and citizen groups urging their representative or senator to act.
Once written in bill form, it is introduced in either the House of Representatives or the Senate, depending on the sponsor.
Step 2: The bill goes to committee
After introduction, the bill is assigned to a committee in that chamber. Committees act as the first major filter in the process. Members research the proposal, debate its effects, and often rewrite it through amendments.
Committees can push a bill forward, change it, or stop it from advancing. In practice, this committee stage decides the fate of many proposals long before the full chamber votes.
Step 3: The chamber votes on the bill
If a committee sends the bill onward, it goes before the full House or full Senate for debate and a vote.
In the House, passage requires a simple majority, which is 218 votes if all 435 members vote.
In the Senate, passage requires a simple majority, which is 51 votes if all 100 senators vote. Senate practice places heavy weight on extended debate prior to voting, which can shape what reaches a final vote and when it happens.
Step 4: The bill repeats the process in the other chamber
A bill that passes one chamber then moves to the other chamber for a broadly similar sequence: committee consideration, possible revisions, debate, and a vote.
This is a second full set of hurdles. Even a bill that sailed through the House can be reshaped in the Senate, and the reverse is equally true.
Step 5: Congress aligns the text
For a bill to reach the president, the House and Senate must pass the same version. When each chamber passes a different version, members work out the differences and both chambers must vote again on the aligned text.
This alignment stage matters. A bill is not “basically done” until both chambers agree to identical language.
Step 6: The bill goes to the president
After both chambers pass the same version, it is presented to the president.
The president has choices:
Sign it, and it becomes law.
Veto it, which sends it back to Congress.
Take no action. If Congress is no longer in session and the bill remains unsigned, it is vetoed by default. This is a pocket veto, and Congress cannot override it.
Step 7: Veto override
A veto does not always end the bill. Congress can override a veto and enact the bill into law, which requires a two thirds vote in both the House and the Senate.
That threshold is intentionally high. It forces broad agreement across both chambers, not just a narrow majority.
The House and Senate do not run the same play
The two chambers are equal in lawmaking power, yet some procedures differ in ways that shape outcomes.
Only the House can initiate tax and revenue legislation.
Only the Senate handles legislation tied to presidential nominations and treaties.
The House moves bills through majority votes under tighter floor procedures, while the Senate places greater weight on deliberation and debate prior to voting.
These differences explain why a proposal can move quickly in one chamber and slow down sharply in the other, even with strong support.
Where bills fail in the real world
Most bills do not become law. The points where they most often stall are structural.
Committee stage, where the bill never gets reported out for a floor vote.
Floor stage, where the chamber votes it down.
Two chamber alignment, where the House and Senate cannot agree on the same text.
Presidential action, where the bill is vetoed and Congress lacks the votes to override.
Each of these is a gate. A bill must clear every gate to become law.
Bill to Law FAQs
What is a bill in the United States?
A bill is a formal proposal for a new federal law or a change to an existing federal law. It must be introduced in Congress, pass the House and Senate in the same form, then be signed by the president or enacted over a veto.
Does a bill need to pass both the House and the Senate?
Yes. Both chambers must approve the same version of the bill. If the House and Senate pass different versions, they must resolve the differences and then vote again on the same text.
What happens if the president vetoes a bill?
A veto returns the bill to Congress. Congress can still enact the bill by overriding the veto with a two thirds vote in both the House and the Senate.
What is a pocket veto?
A pocket veto occurs when the president does not sign a bill and Congress is no longer in session, leaving the bill vetoed by default. Congress cannot override a pocket veto.
What is the main difference between the House and Senate in lawmaking?
Both chambers must pass the same bill, yet they follow different procedures. The House moves legislation through majority votes under tighter floor procedures, while the Senate places greater weight on deliberation and debate prior to voting.
