Only the Senate confirms presidential nominations and approves treaties. In general, House rules and practices allow a numerical majority to process legislation relatively quickly. Congressional action is typically planned and coordinated by party leaders in each chamber, who have been chosen by Members of their own caucus or conference—that is, the group of Members in a chamber who share a party affiliation. Majority party leaders in the House have important powers and prerogatives to effectively set the policy agenda and decide which proposals will receive floor consideration. In the Senate, the leader of the majority party is generally expected to propose items for consideration, but formal tools that allow a numerical majority to take action are few. In both chambers, much of the policy expertise resides in the standing committees—panels of Members from both parties that typically take the lead in developing and assessing legislation. The process by which a bill becomes law is rarely predictable and can vary significantly from bill to bill. In fact, for many bills, the process will not follow the sequence of congressional stages that are often understood to make up the legislative process. This report presents a look at each of the common stages through which a bill may move, but complications and variations abound in practice. In the Senate, bills are typically referred to committee in a similar process, though in almost all cases, the bill is referred to only the committee with jurisdiction over the issue that predominates in the bill. In a limited number of cases, a bill might not be referred to committee, but instead be placed directly on the Senate Calendar of Business through a series of procedural steps on the floor. Hearings11

The first formal committee action on a bill or issue might be a hearing, which provides a forum at which committee Members and the public can hear about the strengths and weaknesses of a proposal from selected parties—like key executive branch agencies, relevant industries, and groups representing interested citizens. A markup concludes when the committee agrees, by majority vote, to report the bill to the chamber. The committee may vote to report a referred bill, with recommended changes that reflect any amendments adopted during the markup. Floor Scheduling

Once a committee has reported a bill, it is placed on one of the respective chambers' calendars. Many will never be brought up on the floor during the course of a two-year Congress. Alternatively, leadership may ask the Rules Committee to start the process of bringing a specific bill to the floor for more lengthy consideration and possible amendments. Most bills are considered under "suspension of the rules" procedures, which limits debate to 40 minutes and does not allow amendments to be offered by Members on the floor. However, for the House to pass a bill under suspension of the rules requires two-thirds of Members voting to agree. called a special rule. Special rules are reported by the House Rules Committee. After debate, the House votes on adopting the special rule; only after its adoption will the House then proceed to consider the bill itself, under the terms specified by the special rule. After the amendment process is complete, the Committee of the Whole reports to the full House any recommended amendments, which are then usually approved by the House by voice vote. Just prior to voting on final passage, Members will typically briefly debate and then vote on a motion to recommit, which allows the minority party to effectively propose its own amendment. Senate Floor Consideration33

To consider a bill on the floor, the Senate first must agree to bring it up—typically by agreeing to a unanimous consent request or by voting to adopt a motion to proceed to the bill, as discussed earlier. Only once the Senate has agreed to consider a bill may Senators propose amendments to it. Perhaps the modern Senate's defining feature is the potential difficulty of reaching a final vote on a matter. Most questions that the Senate considers—from a motion to proceed to a bill, to each amendment, to the bill itself—are not subject to any debate limit. Senate rules provide no way for a simple numerical majority to cut off or otherwise impose a debate limit and move to a final vote. As a result, Senators can wage (or threaten to wage) a filibuster on most amendments, bills, or other motions—in effect, insisting on extended debate or taking other actions intended to delay or prevent a final vote. Overall, these rules and practices governing floor debate and amending in the Senate provide significant leverage to each individual Senator. Rather than relying on the formal rules like cloture, however, frequently the Senate can more effectively act using unanimous consent agreements. Executive Business in the Senate

In addition to full legislative authority, the U.S. Constitution provides the Senate with two unique responsibilities: first, the power to confirm certain presidential nominees to the federal judiciary and certain executive branch positions; and second, the power to approve treaties. In the legislative process, treaties are treated very much like bills: they are referred to the Foreign Relations Committee, where they may be considered and reported. However, the Constitution requires that two-thirds of voting Senators agree for a treaty to be ratified. Resolving Differences Between the Chambers44

A bill must be agreed to by both chambers in the same form before it can be presented to the President. Therefore, at some point in the legislative process, either the House must act on a Senate bill or the Senate must act on a House bill. In this case, when one chamber receives the bill passed by the other, it may act on (and possibly amend) that bill, or alternatively, it may consider (and possibly amend) its own bill first—eventually substituting its language into the other chamber's bill for the purposes of resolving differences between the two proposals. This back-and-forth trading of proposals by the House and Senate is called amendments between the houses (or amendment exchange, or sometimes simply ping-pong). Through a combination of informal negotiations and formal meetings, the conferees try to hammer out a compromise, drawing on elements of the competing proposals that were adopted by each chamber. Reaching a vote on a conference report in the Senate may require a cloture process, and in the House, conference reports are typically considered under a special rule. Beginning at midnight on the closing of the day of presentment, the President has 10 days, excluding Sundays, to sign or veto the bill. If the President vetoes the bill, it is returned to the congressional chamber in which it originated; that chamber may attempt to override the President's veto, though a successful override vote requires the support of two-thirds of those voting. Only if both chambers vote to override does the bill become law notwithstanding the President's veto; successful overrides of a veto are rare.
This report introduces the main steps through which a bill (or other item of business) may travel in the legislative process—from introduction to committee and floor consideration to possible presidential consideration. However, the process by which a bill can become law is rarely predictable and can vary significantly from bill to bill. In fact, for many bills, the process will not follow the sequence of congressional stages that are often understood to make up the legislative process. This report presents a look at each of the common stages through which a bill may move, but complications and variations abound in practice.
Throughout, the report provides references to a variety of other CRS reports that focus on specific elements of congressional procedure. CRS also has many other reports not cited herein that address some procedural issues in additional detail (including congressional budget and appropriations processes). These reports are organized by subissue at http://www.crs.gov/iap/congressional-process-administration-and-elections.
Congressional action on bills typically is planned and coordinated by party leaders in each chamber, though as described in this report, majority party leaders in the House have more tools with which to set the floor agenda than do majority party leaders in the Senate. In both chambers, much of the policy expertise resides in the standing committees, panels of Members who typically take the lead in developing and assessing proposed legislation within specified policy jurisdictions.
Introduction and Referral of Legislation. Once a Member of the House or Senate introduces a bill, it is typically referred to the committee (or committees) in that chamber with jurisdiction over its elements. Committees do not formally consider each of these referred bills. The committee chair has the primary agenda-setting authority for each committee and identifies which bills will receive formal committee attention during the course of the two-year Congress. (Committees are not limited, however, to consideration of measures referred to them and may initiate legislative action on their own.)
Committee Consideration. A committee may conduct hearings on a bill to provide committee members and the public an opportunity to hear from selected parties (e.g., a federal agency or organized interest) about the bill's strengths and weaknesses. If the committee wants to formally recommend that the bill receive consideration from its parent chamber, it will hold a markup on the bill, at which committee members vote on any proposed amendments. The markup concludes when the committee agrees, by majority vote, to report the bill (with any recommended changes adopted in the markup) to its chamber.
Floor Scheduling. In the House, majority party leaders generally decide which bills will receive floor consideration; typically, they schedule a bill for a type of streamlined floor consideration, or instead ask the Rules Committee to propose a set of tailored parameters for floor consideration. In the Senate, bills are brought to the floor only after the Senate agrees to a motion (typically offered by the majority leader) to proceed to a specific bill or, alternatively, if no Senator objects to a unanimous consent request to bring it up.
House Floor Consideration. In the House, most bills that receive consideration do so under a procedure called "suspension of the rules," which limits debate to 40 minutes and prohibits floor amendments, but requires two-thirds of Members voting to agree. Most other bills are considered under tailored debate and amending parameters set by the terms of a special rule reported by the House Rules Committee (which effectively operates as an arm of the majority party leadership). The House first votes to adopt the special rule, and then can proceed to debate and potentially amend the bill (typically accomplished in a setting called Committee of the Whole). After any debate and amending process is complete, the House then typically votes on a minority party alternative (through a vote on a motion to recommit) before proceeding to a final vote on passage.
Senate Floor Consideration. In the Senate, once the chamber has agreed to bring up a bill, it can be considered under rules and practices that allow for a wide-ranging debate and amendment process. A defining feature of Senate floor consideration is that no rule permits a numerical majority to end debate and proceed to a final vote on most questions (e.g., a bill or amendment). Thus, Senators may wage a filibuster, effectively threatening extended debate or other actions that would delay or prevent a final vote. The Senate's cloture rule provides a process, however, by which a supermajority of the Senate (usually three-fifths) can, over a series of days, place a limit on debate (as well as limits on amendments) and eventually reach a final vote. These rules and practices provide extraordinary leverage to individual Senators, but frequently the Senate decides it can more effectively act by putting aside the formal rules and instead agreeing—by unanimous consent—to tailored parameters on debate and amending.
Executive Business in the Senate. The Senate has the unique responsibility to confirm certain presidential nominations and to approve treaties. Nominations and treaties are treated very much like bills: they are referred to committees, where they may be considered and reported to the chamber. On the floor, a ratification of a treaty requires the support of two-thirds of voting Senators. Nominations considered on the floor may be confirmed by a numerical majority, but they are subject to debate, such that reaching a final vote may require a successful cloture process.
Resolving Differences between the Chambers. At some point in the legislative process, either the House must act on a Senate bill, or the Senate must act on a House bill since only one can be presented to the President. One chamber frequently agrees to a bill—without changes—that was sent to it by the other, but sometimes each chamber proposes changes to a bill sent to it by the other. The chambers resolve their differences on the competing proposals either through a back-and-forth trading of alternative proposals (called amendments between the houses), or by convening an ad hoc conference committee in which House and Senate Members from the relevant committees are appointed to hammer out a compromise called a conference report. After both chambers have agreed to identical text (either by agreeing to the other chamber's proposal during amendments between the houses or by agreeing to the conference report), the bill can be presented to the President.
Presidential Action. The President has 10 days, excluding Sundays, to sign or veto a bill. If it is vetoed, it can only become law if Congress agrees—by two-thirds in each chamber, separately—to override the veto. Successful overrides of presidential vetoes are rare, so Congress typically must accommodate the President's position earlier in the process.