Step 1: Introduction and Committee
Any member of Congress can introduce a bill by submitting it to the clerk of their chamber. In the House, bills are dropped into a “hopper” near the clerk’s desk. In the Senate, bills are formally introduced from the floor. Once introduced, a bill is assigned a number (H.R. in the House, S. in the Senate) and referred to the relevant committee or committees with jurisdiction over its subject matter.
Committee markup: The committee reviews the bill, holds hearings where experts and stakeholders testify, and conducts a markup session where members can amend the bill and vote on whether to report it to the full chamber. The vast majority of bills never make it through committee — they simply expire at the end of a Congress without action. Committee chairs have enormous power to advance or kill legislation.
Step 2: Floor Debate and Vote
Once a committee reports a bill, it goes to the full chamber floor for debate and a vote. The process differs significantly between the House and Senate.
In the House: The Rules Committee sets the terms for floor debate: how long debate will last, what amendments can be offered, and whether a bill is considered under an “open rule” (any germane amendment allowed) or “closed rule” (no amendments). The House passes bills by simple majority of those present and voting. The majority party uses its control of the Rules Committee to structure floor action.
In the Senate: There is no equivalent gatekeeper. Under Senate rules, any senator can speak indefinitely (the filibuster), which means most significant legislation effectively requires 60 votes for cloture (ending debate). Exceptions include budget reconciliation bills and executive branch nominations, which require only a simple majority. This means the majority party in the Senate usually needs at least some support from the minority to pass major legislation.
The Legislative Process at a Glance
| Stage | Where | Vote Required | Key Risk |
|---|---|---|---|
| Introduction | House or Senate | None | Referral to hostile committee |
| Committee markup | Committee | Simple majority | Chair refuses to schedule a hearing |
| Floor debate & vote | House & Senate | Simple majority (60 for Senate cloture) | Filibuster, defections |
| Conference / reconciliation | Both chambers | Simple majority (both) | Differences irreconcilable |
| Presidential action | White House | — | Veto, pocket veto |
| Veto override | Both chambers | Two-thirds majority | Rarely achieved |
Step 3: Conference and Presidential Action
Because the House and Senate often pass different versions of the same legislation, differences must be resolved before a bill goes to the president. Formally, a conference committee — members appointed from both chambers — meets to negotiate a compromise. Both chambers must then pass the identical conference report. In modern practice, leadership often skips formal conference in favor of direct negotiation.
Once both chambers pass identical text, the bill goes to the President, who has three options: sign it into law, veto it (returning it to Congress with objections), or take no action. If the president takes no action within 10 days while Congress is in session, the bill becomes law automatically. If Congress has adjourned, inaction constitutes a “pocket veto” and the bill does not become law.
A vetoed bill can become law if two-thirds of both chambers vote to override the veto — a rarely achieved threshold.
Frequently Asked Questions
What happens in a committee markup?
During markup, committee members review the bill line by line, offer amendments, debate changes, and vote. If the committee votes to report the bill, it advances to the full floor. Most bills die in committee without a markup ever being scheduled — committee chairs can effectively kill a bill by refusing to hold hearings on it.
What is a conference committee?
A conference committee resolves differences between the House and Senate versions of a bill. Members from both chambers meet, negotiate a compromise, and produce a conference report that both chambers must then pass without amendment. Formal conference committees have become rare — most major bills are now resolved through direct leadership negotiation or sequential amendment between chambers.
How is a presidential veto overridden?
Both chambers must pass the same bill again by a two-thirds majority: 290+ votes in the 435-member House, 67+ votes in the 100-member Senate. This is a very high bar and is rarely met. Presidents typically only veto bills when they know there is no supermajority to override, so veto overrides are uncommon in modern Congresses.
