Filibuster Explorer

The Senate glossary defines a filibuster as an attempt to block or delay Senate action by debating at length, offering numerous procedural motions or other delaying actions. U.S. Senate

Cloture is the Senate procedure that places a time limit on consideration of a bill or other matter, used to overcome or deter a filibuster. U.S. Senate

How the Filibuster and Cloture Developed

• Until 1917 the Senate rules did not provide a way to end debate and force a vote on a measure. That year the Senate adopted a rule letting a two-thirds majority end a filibuster, a procedure called cloture. U.S. Senate
• The Senate first invoked cloture in 1919, to end a filibuster against the Treaty of Versailles. U.S. Senate
• In 1975 the Senate lowered the cloture vote from two-thirds of senators voting to three-fifths of all senators duly chosen and sworn, or 60 of the 100-member Senate. U.S. Senate

How Cloture Works

• A cloture motion must be signed by 16 senators, and it can be filed on any measure, motion or other matter pending before the Senate. U.S. Senate
• The Senate votes on a cloture motion one hour after it meets on the second calendar day after the motion is presented. Once a quorum is confirmed, the vote is a roll call, taken without debate. U.S. Senate
• Cloture takes three-fifths of the senators duly chosen and sworn, except on a measure or motion to amend the Senate rules, which takes two-thirds of the senators present and voting. U.S. Senate
• After cloture, no senator may speak more than one hour in all, and after no more than 30 hours of consideration the Senate votes on the measure without further debate. U.S. Senate
• After cloture, dilatory motions, dilatory amendments and amendments that are not germane are out of order. U.S. Senate
• A motion to proceed brings a measure, nomination or treaty up for floor debate and votes, usually when the Senate can’t get unanimous consent to take it up. U.S. Senate
• Rule XXII, the Senate’s cloture rule, also covers cloture on a motion to proceed to a measure. If 16 senators sign, including both party leaders and seven more senators from each side, the vote comes one hour after the Senate meets on the next calendar day, a day sooner than usual. Once cloture is invoked, the Senate votes on the motion to proceed without further debate. U.S. Senate
• Unanimous consent sets aside a rule of procedure to speed things up, for example by limiting debate time, but if any senator objects, the request is rejected. U.S. Senate

Nominations and the Nuclear Option

• The president nominates, and with the Senate’s advice and consent appoints, ambassadors, Supreme Court justices and other officers of the United States. U.S. Constitution
• As of Sept. 25, 2026, the Senate’s filibuster history page says filibusters remain part of Senate practice only on legislation. It says the Senate adopted new precedents in the 2010s letting a simple majority end debate on nominations. U.S. Senate
• The Senate’s history of judicial nominations says that in the 21st century, lower court nominations were filibustered for the first time, and invoking cloture to end debate on them took a three-fifths majority, or 60 votes. U.S. Senate
• In 2013 the Senate used what is called the nuclear option, a procedural move that lowered the vote needed to end debate on lower court judicial nominees to a simple majority. U.S. Senate
• After a January 2017 Supreme Court nomination, the Senate used the nuclear option again, lowering the cloture threshold for Supreme Court nominees to a simple majority. U.S. Senate
• The edition of the Senate standing rules ordered printed on June 14, 2022, sets cloture at three-fifths of the senators duly chosen and sworn, with two-thirds of those present and voting for a change to the rules. U.S. Senate
• The Senate treats precedents set by the presiding officer and by senators’ votes as just as important as its standing rules, and the parliamentarian’s office keeps the records of them. U.S. Senate

The sources cited here don’t state the vote needed to confirm a nominee; Article II requires the Senate’s advice and consent.

Budget Reconciliation and the Byrd Rule

• Reconciliation is an optional process under the Congressional Budget Act of 1974 through which Congress changes existing laws to bring tax and spending levels in line with a budget resolution. U.S. Senate
• Reconciliation instructions in a budget resolution direct committees to send the Budget Committee legislation making the changes, usually by a deadline, and the result is a reconciliation bill. U.S. Senate
• Senate debate on a budget resolution, including amendments, debatable motions and appeals, is limited to 50 hours. U.S. Code
• Senate debate on a reconciliation bill, including all amendments, debatable motions and appeals, is limited to 20 hours. U.S. Code
• In the Senate, the procedures the law sets for budget resolutions also apply to reconciliation bills, except that the reconciliation debate limit is 20 hours. U.S. Code
• Under those procedures, debate on each amendment is limited to two hours, and an amendment that is not germane is not received. U.S. Code
• After debate time runs out on a budget resolution or reconciliation bill, senators can offer an unlimited number of amendments, each voted on in succession, a process known as a vote-arama. U.S. Senate
• A reconciliation bill may not contain recommendations about Social Security’s old-age, survivors and disability insurance program. U.S. Code
• The rule against extraneous matter in reconciliation bills became known as the Byrd rule, after an amendment Sen. Robert C. Byrd of West Virginia offered in 1985. Riddick’s Senate Procedure
• Any senator may raise a point of order against material in a reconciliation bill that is extraneous to a committee’s instructions. If the chair upholds it, that material is struck and can’t be offered again as a floor amendment. U.S. Code
• The Byrd rule can be waived in the Senate only by three-fifths of the senators duly chosen and sworn, and it takes the same three-fifths vote to overturn the chair’s ruling on it. U.S. Code

What counts as extraneous

• A provision is extraneous if it doesn’t change outlays or revenues. U.S. Code
• A provision that increases outlays or cuts revenues is extraneous if the reporting committee fails to meet its reconciliation instructions. U.S. Code
• A provision outside the jurisdiction of the committee that reported it is extraneous. U.S. Code
• A provision whose budget effects are merely incidental to its non-budget parts is extraneous. U.S. Code
• A provision that increases net outlays or cuts revenues in a year after the years the bill covers is extraneous, unless other provisions in its title offset it that year. U.S. Code
• A provision that breaks the reconciliation law’s bar on Social Security changes is extraneous. U.S. Code

Congressional Review Act Resolutions

• A Congressional Review Act resolution is a joint resolution saying that Congress disapproves an agency’s rule and that the rule shall have no force or effect. U.S. Code
• The expedited procedure covers only a disapproval resolution introduced within 60 days after Congress receives the agency’s report on the rule, not counting days either chamber is adjourned for more than three days. U.S. Code
• If the Senate committee hasn’t reported the resolution 20 calendar days after the rule is submitted or published, a petition signed by 30 senators discharges it to the Senate calendar. U.S. Code
• A motion to take up the resolution is in order at any time after that and can’t be amended or postponed. All points of order against the resolution are waived. U.S. Code
• Senate debate on a Congressional Review Act disapproval resolution and related motions and appeals is limited to 10 hours, split equally between supporters and opponents, and no amendment is allowed. U.S. Code
• The vote on final passage comes right after debate ends, with a single quorum call if requested. U.S. Code
• The Senate’s expedited procedure for a disapproval resolution is available only for 60 session days beginning with the date the rule is submitted or published. In some cases, the 60 session days instead begin on the 15th session day after the next session of Congress convenes. U.S. Code
• The president can veto a disapproval resolution Congress passes, and the law addresses what happens when either chamber votes and fails to override that veto. U.S. Code
• A resolution that needs both chambers’ agreement, other than on adjournment, goes to the president too. If the president disapproves, two-thirds of the Senate and the House must pass it again. U.S. Constitution
• Once a disapproval resolution is enacted, the rule can’t take effect or continue. The agency can’t reissue it or issue a substantially similar rule unless a later law specifically authorizes it. U.S. Code

Treaties, Veto Overrides, Amendments, Impeachment and Expulsion

• The Constitution requires a two-thirds vote of the Senate in a few instances, including expelling a senator, overriding a veto, proposing a constitutional amendment, convicting an impeached official and consenting to ratification of a treaty. U.S. Senate
• The president makes treaties with the Senate’s advice and consent, provided two-thirds of the senators present concur. U.S. Constitution
• The Senate doesn’t ratify treaties. It approves or rejects a resolution of ratification. If the resolution passes, ratification takes place when the countries formally exchange the instruments of ratification. U.S. Senate
• A bill the president vetoes becomes law only if two-thirds of each house votes to pass it again, with each member’s vote recorded by name. U.S. Constitution
• The Senate’s precedents book, Riddick’s Senate Procedure (1992), says the Constitution requires a yea-and-nay vote to pass a bill over a veto. It puts the vote required at two-thirds of the senators voting, as long as a quorum is present. Riddick’s Senate Procedure
• Congress proposes a constitutional amendment when two-thirds of both houses deem it necessary, and it becomes part of the Constitution when ratified by the legislatures of, or conventions in, three-fourths of the states. U.S. Constitution
• In the National Prohibition Cases (1920), the Supreme Court held that each house must propose an amendment by two-thirds of the members present, assuming a quorum, rather than two-thirds of the entire membership. Constitution Annotated
• Article V also has Congress call a convention to propose amendments on the application of two-thirds of the state legislatures, but proposal by Congress is the only method used so far. Constitution Annotated
• The Senate alone tries impeachments, and no one may be convicted without two-thirds of the senators present. U.S. Constitution
• Each house may expel a member with the concurrence of two-thirds. U.S. Constitution
• A Senate quorum is a majority of the senators duly chosen and sworn. U.S. Senate

Changing the Senate’s Rules

• The Constitution lets each house determine the rules of its proceedings. U.S. Constitution
• The Senate is governed by the Constitution, its standing rules, precedents set in the course of the legislative process, and special rules of procedure that laws set for particular types of legislation. U.S. Senate
• A motion to amend a Senate rule needs one day’s written notice specifying the rule and the purpose of the change. U.S. Senate
• Cloture takes three-fifths of the senators duly chosen and sworn, except on a measure or motion to amend the Senate rules, which takes two-thirds of the senators present and voting. U.S. Senate
• A measure changing the Senate’s rules needs a two-thirds vote to invoke cloture, but only a simple majority to adopt it. U.S. Senate
• The Senate’s rules continue from one Congress to the next unless they are changed as the rules provide. U.S. Senate
• The Senate treats precedents set by the presiding officer and by senators’ votes as just as important as its standing rules, and the parliamentarian’s office keeps the records of them. U.S. Senate

Related GovFacts Articles

• The Filibuster and Cloture: How the Senate Really Works
• The Senate Filibuster: What It Is and Why It’s Controversial
• Understanding Budget Reconciliation and Regular Order in the U.S. Congress
• Why Most Bills Never Become Law: The Hidden Chokepoints in Congress
• Congressional Review Act vs. Administrative Procedure Act: Your Guide to Federal Rulemaking and Congressional Oversight
• Decoding the Veto: Understanding the President’s Power to Say “No” to Congress