	Introduction

The filibuster is widely viewed as one of the Senate's most distinctive procedural features. More generally, however, filibustering includes any tactics aimed at blocking a measure by preventing it from coming to a vote. Instead, possibilities for filibustering exist because Senate rules lack provisions that would place specific limits on Senators' rights and opportunities in the legislative process. This report discusses major aspects of Senate procedure related to filibusters and cloture. The report does not encompass all possible contingencies or consider every relevant precedent, though it identifies key modifications to the rule and its application in recent years. The Right to Speak at Length and the Two-Speech Rule

Under Rule XIX, unless any special limits on debate are in effect, Senators who have been recognized may speak for as long as they wish. The motion is not debatable, and its adoption requires only a simple majority vote. By this means, Senators can prevent a debate from continuing indefinitely if they are prepared to reject the amendment, motion, or bill that is being debated. A quorum is rarely present, and the presiding officer normally does not have the authority to count to determine whether a quorum actually is present; he or she therefore directs the clerk to call the roll. A filibustering Senator has only to suggest the absence of a quorum and then object to calling off the quorum call in order to provoke a motion to secure the attendance of absentees and (with the support of at least 10 other Senators) a roll call vote on that motion. For example, it is not in order for a Senator to present a motion to invoke cloture on a bill the Senate has not yet agreed to consider or on an amendment that has not yet been offered. As a compromise, the Senate agreed to move from two-thirds of the Senators present and voting (a maximum of 67 votes) to three-fifths of the Senators duly chosen and sworn (normally, and at a maximum, 60 votes) on all matters except future rules changes, including changes in the cloture rule itself. In relation to the Senate's initial consideration of a bill or resolution, there usually can be at least two filibusters under the Senate's standing rules: first, a filibuster on the motion to proceed to the measure's consideration; and second, after the Senate agrees to this motion, a filibuster on the measure itself. Time for Consideration and Debate

In general, Rule XXII imposes a cap of no more than 30 additional hours for the Senate to consider a question after invoking cloture on it. Offering Amendments and Motions

There are several key restrictions governing the amendments that Senators can propose under cloture that do not apply to Senate floor amendments under most other circumstances. The relevant portion of Rule XXII reads,
Except by unanimous consent, no amendment shall be proposed after the vote to bring the debate to a close, unless it had been submitted in writing to the Journal Clerk by 1 o'clock p.m. on the day following the filing of the cloture motion if an amendment in the first degree, and unless it had been so submitted at least one hour prior to the beginning of the cloture vote if an amendment in the second degree. For this reason, filibusters and the prospect of filibusters shape much of the way in which the Senate does its work on the floor. The votes of only a majority of Senators present and voting are needed to pass a bill on the floor. It can, however, require the votes of 60 Senators to invoke cloture on the bill in order to overcome a filibuster and enable the Senate to reach that vote on final passage.
The filibuster is widely viewed as one of the Senate's most characteristic procedural features. Filibustering includes any use of dilatory or obstructive tactics to block a measure by preventing it from coming to a vote. The possibility of filibusters exists because Senate rules place few limits on Senators' rights and opportunities in the legislative process.
In particular, a Senator who seeks recognition usually has a right to the floor if no other Senator is speaking, and then that Senator may speak for as long as he or she wishes. Also, there is no motion by which a simple majority of the Senate can stop a debate and allow itself to vote in favor of an amendment, a bill or resolution, or most other debatable questions. Most bills, indeed, are potentially subject to at least two filibusters before the Senate votes on final passage: first, a filibuster on a motion to proceed to the bill's consideration and, second, after the Senate agrees to this motion, a filibuster on the bill itself.
Senate Rule XXII, however, known as the cloture rule, enables Senators to end a filibuster on any debatable matter the Senate is considering. Sixteen Senators initiate this process by presenting a motion to end the debate. In most circumstances, the Senate does not vote on this cloture motion until the second day of session after the motion is made. Then, it requires the votes of at least three-fifths of all Senators (normally 60 votes) to invoke cloture. (Invoking cloture on a proposal to amend the Senate's standing rules requires the support of two-thirds of the Senators present and voting, whereas cloture on nominations requires a numerical majority.)
The primary effect of invoking cloture on most questions is to impose a maximum of 30 additional hours for considering that question. This 30-hour period for consideration encompasses all time consumed by roll call votes, quorum calls, and other actions, as well as the time used for debate. Under cloture, as well, the only amendments Senators can offer are ones that are germane and were submitted in writing before the cloture vote took place. Finally, the presiding officer also enjoys certain additional powers under cloture such as, for example, the power to count to determine whether a quorum is present and to rule amendments, motions, and other actions out of order on the grounds that they are dilatory.
The ability of Senators to engage in filibusters has a profound and pervasive effect on how the Senate conducts its business on the floor. In the face of a threatened filibuster, for example, the majority leader may decide not to call a bill up for floor consideration or may defer calling it up if there are other, equally important bills the Senate can consider and pass with less delay. Similarly, the prospect of a filibuster can persuade a bill's proponents to accept changes in the bill that they do not support but that are necessary to prevent an actual filibuster.
This report concentrates on the operation of cloture under the general provisions of Senate Rule XXII, paragraph 2, though it also identifies key modifications to its application in recent years. This report will be updated as events warrant.