Filibuster in the United States Senate

A filibuster in the United States Senate is a dilatory or obstructive tactic used in the United States Senate to prevent a measure from being brought to a vote. The most common form of filibuster occurs when one or more senators attempts to delay or block a vote on a bill by extending debate on the measure. The Senate rules permit a senator, or a series of senators, to speak for as long as they wish, and on any topic they choose, unless "three-fifths of the Senators duly chosen and sworn" (usually 60 out of 100) bring the debate to a close by invoking cloture under Senate Rule XXII.

The ability to block a measure through extended debate was an inadvertent side effect of an 1806 rule change, and was infrequently used during much of the 19th and 20th centuries. In 1970, the Senate adopted a "two-track" procedure to prevent filibusters from stopping all other Senate business. The minority then felt politically safer in threatening filibusters more regularly, which became normalized over time to the point that 60 votes are now required to end debate on nearly every controversial legislative item. As a result, the modern "filibuster" rarely manifests as an extended floor debate. Instead, "the contemporary Senate has morphed into a 60-vote institution — the new normal for approving measures or matters — a fundamental transformation from earlier years." This effective supermajority requirement has had very significant policy and political impacts on Congress and the other branches of government.

Beginning in 1917 with the cloture rule and especially since the 1970s, there have been efforts to limit the practice. These include laws that explicitly limit Senate debate, notably the Congressional Budget and Impoundment Control Act of 1974 that created the budget reconciliation process. More recently, changes in 2013 and 2017 now require only a simple majority to invoke cloture on nominations, although legislation still requires 60 votes.

One or more senators may still occasionally hold the floor for an extended period, sometimes without the advance knowledge of the Senate leadership. However, these "filibusters" usually result only in brief delays and are not outcome-determinative, since the Senate's ability to act ultimately depends upon whether there are sufficient votes to invoke cloture and proceed to a final vote on passage. However, such brief delays can be politically relevant when exercised shortly before a major deadline (such as avoiding a government shutdown) or before a Senate recess.

History

Constitutional design: simple majority voting

Although not explicitly mandated, the Constitution and its framers clearly envisioned that simple majority voting would be used to conduct business. The Constitution provides, for example, that a majority of each House constitutes a quorum to do business. Meanwhile, a small number of super-majority requirements were explicitly included in the original document, including conviction on impeachment charges (2/3 of Senate), expelling a member of Congress (2/3 of the chamber in question), overriding presidential vetoes (2/3 of both Houses), ratifying treaties (2/3 of Senate) and proposing constitutional amendments (2/3 of both Houses). Through negative textual implication, the Constitution also gives a simple majority the power to set procedural rules: "Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behaviour, and, with the Concurrence of two thirds, expel a Member."

Commentaries in The Federalist Papers confirm this understanding. In Federalist No. 58, the Constitution's primary drafter James Madison defended the document against routine super-majority requirements, either for a quorum or a "decision":

"It has been said that more than a majority ought to have been required for a quorum; and in particular cases, if not in all, more than a majority of a quorum for a decision. That some advantages might have resulted from such a precaution, cannot be denied. It might have been an additional shield to some particular interests, and another obstacle generally to hasty and partial measures. But these considerations are outweighed by the inconveniences in the opposite scale.

"In all cases where justice or the general good might require new laws to be passed, or active measures to be pursued, the fundamental principle of free government would be reversed. It would be no longer the majority that would rule: the power would be transferred to the minority. Were the defensive privilege limited to particular cases, an interested minority might take advantage of it to screen themselves from equitable sacrifices to the general weal, or, in particular emergencies, to extort unreasonable indulgences."

In Federalist No. 22, Alexander Hamilton described super-majority requirements as being one of the main problems with the previous Articles of Confederation, and identified several evils which would result from such a requirement:

"To give a minority a negative upon the majority (which is always the case where more than a majority is requisite to a decision), is, in its tendency, to subject the sense of the greater number to that of the lesser. ... The necessity of unanimity in public bodies, or of something approaching towards it, has been founded upon a supposition that it would contribute to security. But its real operation is to embarrass the administration, to destroy the energy of the government, and to substitute the pleasure, caprice, or artifices of an insignificant, turbulent, or corrupt junto, to the regular deliberations and decisions of a respectable majority. In those emergencies of a nation, in which the goodness or badness, the weakness or strength of its government, is of the greatest importance, there is commonly a necessity for action. The public business must, in some way or other, go forward. If a pertinacious minority can control the opinion of a majority, respecting the best mode of conducting it, the majority, in order that something may be done, must conform to the views of the minority; and thus the sense of the smaller number will overrule that of the greater, and give a tone to the national proceedings. Hence, tedious delays; continual negotiation and intrigue; contemptible compromises of the public good. And yet, in such a system, it is even happy when such compromises can take place: for upon some occasions things will not admit of accommodation; and then the measures of government must be injuriously suspended, or fatally defeated. It is often, by the impracticability of obtaining the concurrence of the necessary number of votes, kept in a state of inaction. Its situation must always savor of weakness, sometimes border upon anarchy.

Accidental creation and early use of the filibuster

In 1789, the first U.S. Senate adopted rules allowing senators to move the previous question (by simple majority vote), which meant ending debate and proceeding to a vote. But in 1806, the Senate's presiding officer, Vice President Aaron Burr argued that the previous-question motion was redundant, had only been exercised once in the preceding four years, and should be eliminated. The Senate agreed and modified its rules. Because it created no alternative mechanism for terminating debate, filibusters became theoretically possible.

Nevertheless, in the early 19th century the principle of simple-majority voting in the Senate was well established, and particularly valued by Southern slave-holding states. New states were admitted to the Union in pairs to preserve the sectional balance in the Senate, most notably in the Missouri Compromise of 1820.

Until the late 1830s, however, the filibuster remained a solely theoretical option, never actually exercised. The first Senate filibuster occurred in 1837. In 1841, a defining moment came during debate on a bill to charter the Second Bank of the United States. Senator Henry Clay tried to end the debate via majority vote, and Senator William R. King threatened a filibuster, saying that Clay "may make his arrangements at his boarding house for the winter." Other senators sided with King, and Clay backed down.

At the time, both the Senate and the House of Representatives allowed filibusters as a way to prevent a vote from taking place. Subsequent revisions to House rules limited filibuster privileges in that chamber, but the Senate continued to allow the tactic.

In practice, narrow majorities could enact legislation by changing the Senate rules, but only on the first day of the session in January or March.

The emergence of cloture (1917–1969)

In 1917, during World War I, a rule allowing cloture of a debate was adopted by the Senate on a 76-3 roll call vote at the urging of President Woodrow Wilson, after a group of 12 anti-war senators managed to kill a bill that would have allowed Wilson to arm merchant vessels in the face of unrestricted German submarine warfare.

From 1917 to 1949, the requirement for cloture was two-thirds of senators voting. Despite that formal requirement, however, political scientist David Mayhew has argued that in practice, it was unclear whether a filibuster could be sustained against majority opposition. During the 1930s, Senator Huey Long of Louisiana used the filibuster to promote his populist policies. He recited Shakespeare and read out recipes for "pot-likkers" during his filibusters, which occupied 15 hours of debate. In 1946, five Southern Democrats — senators John H. Overton (La.), Richard B. Russell (Ga.), Senator Millard E. Tydings (Md.), Clyde R. Hoey (N.C.), and Kenneth McKellar (Tenn.) — blocked a vote on a bill (S. 101) proposed by Democrat Dennis Chávez of New Mexico that would have created a permanent Fair Employment Practice Committee (FEPC) to prevent discrimination in the workplace. The filibuster lasted weeks, and Senator Chávez was forced to remove the bill from consideration after a failed cloture vote, even though he had enough votes to pass the bill.

In 1949, the Senate made invoking cloture more difficult by requiring two-thirds of the entire Senate membership to vote in favor of a cloture motion. Moreover, future proposals to change the Senate rules were themselves specifically exempted from being subject to cloture. In 1953, Senator Wayne Morse of Oregon set a record by filibustering for 22 hours and 26 minutes while protesting the Tidelands Oil legislation. Senator Strom Thurmond of South Carolina broke this record in 1957 by filibustering the Civil Rights Act of 1957 for 24 hours and 18 minutes, although the bill ultimately passed.

In 1959, anticipating more civil rights legislation, the Senate under the leadership of Majority Leader Lyndon Johnson restored the cloture threshold to two-thirds of those voting. Although the 1949 rule had eliminated cloture on rules changes themselves, Johnson acted at the very beginning of the new Congress on January 5, 1959, and the resolution was adopted by a 72-22 vote with the support of three top Democrats and three of the four top Republicans. The presiding officer, Vice President Richard Nixon, supported the move and stated his opinion that the Senate "has a constitutional right at the beginning of each new Congress to determine rules it desires to follow." The 1959 change also eliminated the 1949 exemption for rules changes, allowing cloture to once again be invoked on future changes.

One of the most notable filibusters of the 1960s occurred when Southern Democrats attempted to block the passage of the Civil Rights Act of 1964 by filibustering for 75 hours, including a 14 hour and 13 minute address by Senator Robert Byrd of West Virginia. The filibuster failed when the Senate invoked cloture for only the second time since 1927.

The two-track system, 60-vote rule and rise of the routine filibuster (1970 onward)

After a series of filibusters in the 1960s over civil rights legislation, the Senate put a "two-track system" into place in 1970 under the leadership of Majority Leader Mike Mansfield and Majority Whip Robert Byrd. Before this system was introduced, a filibuster would stop the Senate from moving on to any other legislative activity. Tracking allows the majority leader—with unanimous consent or the agreement of the minority leader—to have more than one bill pending on the floor as unfinished business. Under the two-track system, the Senate can have two or more pieces of legislation pending on the floor simultaneously by designating specific periods during the day when each one will be considered.

Cloture voting in the United States Senate since 1917.

The notable side effect of this change was that by no longer bringing Senate business to a complete halt, filibusters on particular legislation became politically easier for the minority to sustain. As a result, the number of filibusters began increasing rapidly, eventually leading to the modern era in which an effective supermajority requirement exists to pass legislation, with no practical requirement that the minority party actually hold the floor or extend debate.

In 1975, the Senate revised its cloture rule so that three-fifths of sworn senators (60 votes out of 100) could limit debate, except for changing Senate rules which still requires a two-thirds majority of those present and voting to invoke cloture. However, by returning to an absolute number of all Senators (60) rather than a proportion of those present and voting, the change also made any filibusters easier to sustain on the floor by a small number of senators from the minority party without requiring the presence of their minority colleagues. This further reduced the majority's leverage to force an issue through extended debate.

The Senate also experimented with a rule that removed the need to speak on the floor in order to filibuster (a "talking filibuster"), thus allowing for "virtual filibusters". Another tactic, the post-cloture filibuster—which used points of order to delay legislation because they were not counted as part of the limited time allowed for debate—was rendered ineffective by a rule change in 1979.

As the filibuster has evolved from a rare practice that required holding the floor for extended periods into a routine 60-vote supermajority requirement, Senate leaders have increasingly used cloture motions as a regular tool to manage the flow of business, often even in the absence of a threatened filibuster. Thus, the presence or absence of cloture attempts is not necessarily a reliable indicator of the presence or absence of a threatened filibuster. Because filibustering does not depend on the use of any specific rules, whether a filibuster is present is always a matter of judgment.

Recent efforts to limit filibusters

In 2005, a group of Republican senators led by Majority Leader Bill Frist proposed having the presiding officer, Vice President Dick Cheney, rule that a filibuster on judicial nominees was unconstitutional, as it was inconsistent with the President's power to name judges with the advice and consent of a simple majority of senators. This was a response to the Democrats' threat to filibuster some judicial nominees of President George W. Bush. Senator Trent Lott, the junior senator from Mississippi, used the word "nuclear" to describe the plan, and so it became known as the "nuclear option".

With Republicans effectively controlling the Senate 55-45, a group of 14 senators—seven Democrats and seven Republicans, collectively dubbed the "Gang of 14"—reached an agreement to defuse the conflict. The seven Democrats promised not to filibuster Bush's nominees except under "extraordinary circumstances", while the seven Republicans promised to oppose the "nuclear option" unless they thought a nominee was being filibustered under non-extraordinary circumstances. Thus, there would be 62 votes to invoke cloture in most cases, and 52 votes to oppose the nuclear option. This agreement was successful in the short term, but it expired in January 2007, at the end of the second session of the 109th United States Congress.

From April to June 2010, under Democratic control, the Senate Committee on Rules and Administration held a series of monthly public hearings on the history and use of the filibuster in the Senate. In response to the use of the filibuster in the 111th Congress, all Democratic senators returning to the 112th Congress signed a petition to Majority Leader Harry Reid (D-Nevada) requesting that the filibuster be reformed, including abolishing secret holds and reducing the amount of time allotted for post-cloture debate.

Minor 2013 changes

During the 113th Congress, two packages of amendments were adopted on January 25, 2013. Changes to standing orders affecting just the 2013–14 Congress (Senate Resolution 15) were passed by a vote of 78 to 16, allowing Reid, the majority leader, to prohibit a filibuster on a motion to begin consideration of a bill. Changes to the permanent Senate rules (Senate Resolution 16) were passed by a vote of 86 to 9.

The changes removed the 60-vote requirement to begin debate on legislation, and allowed the minority two amendments to measures that reached the Senate floor. This change was implemented as a standing order that expired at the end of the term in which it was passed. The new rules also reduced the amount of time allowed for debate after a motion to proceed from 30 hours to four hours. Additionally, they stated that a filibuster on a motion to proceed could be blocked with a petition signed by eight members of the minority, including the minority leader. For district court nominations, the new rules reduced the maximum time between cloture and a confirmation vote from 30 hours to two hours. Finally, if senators wished to block a bill or nominee after the motion to proceed, they had to be present in the Senate and debate.

Despite these changes, 60 votes were still required to overcome a filibuster, and the "silent filibuster"—in which a senator can delay a bill even if they leave the floor—remained in place.

Abolition for nominations: 2013 and 2017

On November 21, 2013, the Senate used the so-called "nuclear option," voting 52–48 — with all Republicans and three Democrats opposed — to eliminate the use of the filibuster on executive branch nominees and judicial nominees, except to the Supreme Court. At the time of the vote, there were 59 executive branch nominees and 17 judicial nominees awaiting confirmation.

The Democrats' stated motivation was what they saw as an expansion of filibustering by Republicans during the Obama administration, especially with respect to nominations for the United States Court of Appeals for the District of Columbia Circuit. Republicans had asserted that the D.C. Circuit was underworked and cited a need to cut costs by reducing the number of judges. Democrats responded that Republicans had not raised these concerns earlier, when President Bush had made nominations to the court, and argued that the size of the court needed to be maintained because of the complexity of the cases it hears. Senate Democrats who supported the "nuclear option" also did so out of frustration with filibusters of executive branch nominees for agencies such as the Federal Housing Finance Agency.

In 2015, Republicans took control of the Senate and kept the 2013 rules in place. Finally, on April 6, 2017, the Senate eliminated the sole remaining exception to the 2013 change by invoking the "nuclear option" for Supreme Court nominees. This was done in order to allow a simple majority to confirm Neil Gorsuch to the Supreme Court. The vote to change the rules was 52 to 48 along party lines.

Exceptions

The only bills that are not currently subject to effective 60-vote requirements are those considered under provisions of law that limit time for debating them. These limits on debate allow the Senate to hold a simple-majority vote on final passage without obtaining the 60 votes normally needed to close debate. As a result, many major legislative actions in recent decades have been adopted through one of these methods.

Reconciliation is a procedure created in 1974 as part of the congressional budget process. In brief, the annual budget process begins with adoption of a budget resolution (passed by simple majority in each house, not signed by President, does not carry force of law) that sets overall funding levels for the government. The Senate may then consider a budget reconciliation bill, not subject to filibuster, that reconciles funding amounts in any annual appropriations bills with the amounts specified in the budget resolution. However, under the Byrd rule no non-budgetary "extraneous matter" may be considered in a reconciliation bill. The presiding officer, relying always (as of 2017) on the opinion of the Senate parliamentarian, determines whether an item is extraneous, and a 60-vote majority is required to include such material in a reconciliation bill.

The Congressional Review Act, adopted in 1995, allows Congress to review and repeal administrative regulations adopted by the Executive Branch within 60 legislative days. This procedure will most typically be used successfully shortly after a party change in the presidency. It was used once in 2001 to repeal an ergonomics rule promulgated under Bill Clinton), was not used in 2009, and was used 14 times in 2017 to repeal various regulations adopted in the final year of the Barack Obama presidency.

Policy and political effects

The modern-era filibuster — and the effective 60-vote supermajority requirement it has led to — have had very major policy and political effects, both institutionally and on specific major policy initiatives from Presidents of both parties.

Institutional effects

Congress. The supermajority rule has made it very difficult, often impossible, for Congress to pass any but the most non-controversial legislation in recent decades. During times of unified party control, majorities have attempted (with varying levels of success) to enact their major policy priorities through the budget reconciliation process, resulting in legislation constrained by budget rules. Meanwhile, public approval for Congress as an institution has fallen to its lowest levels ever, with large segments of the public seeing the institution as ineffective. Shifting majorities of both parties — and their supporters — have often been frustrated as major policy priorities articulated in political campaigns are unable to obtain passage following an election.

The Presidency. Presidents of both parties have increasingly filled the policymaking vacuum with expanded use of executive power, including executive orders in areas that had traditionally been handled through legislation. For example, Barack Obama effected major changes in immigration policy by issuing work permits to some undocumented workers, while Donald Trump has issued several significant executive orders since taking office in 2017 along with undoing many of Obama's initiatives. As a result, policy in these areas is increasingly determined by executive preference, and is more easily changed after elections, rather than through more permanent legislative policy.

Judiciary. The Supreme Court's caseload has declined significantly, with various commenters suggesting that the decline in major legislation has been a major cause. Meanwhile, more policy issues are resolved judicially without action by Congress — despite the existence of potential simple majority support in the Senate — on topics such as the legalization of same-sex marriage.

Major presidential policy initiatives

The implied threat of a filibuster — and the resulting 60-vote requirement in the modern era — have had major impacts on the ability of recent Presidents to enact their top legislative priorities into law. The effects of the 60-vote requirement are most apparent in periods where the President and both Houses of Congress are controlled by the same political party, typically early in a presidential term.

Bill Clinton

In 1993-94, President Bill Clinton enjoyed Democratic majorities in both chambers of the 103rd Congress, including a 57-43 advantage in the Senate. Yet the Clinton health care plan of 1993, formulated by a task force led by First Lady Hillary Clinton, was unable to pass in part due to the filibuster. As early as April 1993, a memo to the task force noted that "While the substance is obviously controversial, there is apparently great disquiet in the Capitol over whether we understand the interactivity between reconciliation and health, procedurally, and in terms of timing and counting votes for both measures...."

George W. Bush

In 2001, President George W. Bush was unable to obtain any Democratic support for his tax cut proposals. As a result, the Bush tax cuts of 2001 and 2003 were each passed using reconciliation, which required that the tax cuts expire within the 10-year budget window to avoid violating the Byrd rule in the Senate. The status of the tax cuts would remain unresolved until the late 2012 " fiscal cliff," with a significant portion of the cuts being made permanent by the American Taxpayer Relief Act of 2012, passed by a Republican Congress and signed by President Barack Obama.

Barack Obama

In 2009-10, President Barack Obama briefly enjoyed an effective 60-vote Democratic majority (including independents) in the Senate during the 111th Congress. During that time period, the Senate passed the Patient Protection and Affordable Care Act, commonly known as the ACA or "Obamacare," on Dec. 24, 2009 by a vote of 60-39 (after invoking cloture by the same 60-39 margin). However, Obama's proposal to create a public health insurance option was removed from the health care legislation because it could not command 60-vote support.

House Democrats did not approve of all aspects of the Senate bill, but after 60-vote Senate control was permanently lost in February 2010 due to the election of Scott Brown to fill the seat of the late Ted Kennedy, House Democrats decided to pass the Senate bill intact and it became law. Several House-desired modifications to the Senate bill — those sufficient to pass scrutiny under the Byrd rule — were then made under reconciliation via the Health Care and Education Reconciliation Act of 2010, which was enacted days later following a 56-43 vote in the Senate.

The near-60-vote Senate majority that Democrats held throughout the 111th Congress was also critical to passage of other major Obama initiatives, including the American Reinvestment and Recovery Act of 2009 (passed 60-38, two Republicans voting yes) and the Dodd-Frank Wall Street Reform and Consumer Protection Act (passed 60-39, three Republicans voting yes, one Democrat voting no). However, the House-passed American Clean Energy and Security Act, which would have created a cap-and-trade system and established a national renewable electricity standard to combat climate change, never received a Senate floor vote with Majority Leader Harry Reid saying "it's easy to count to 60."

Donald Trump

In 2017, President Donald Trump and the 115th Congress pursued a strategy to use an FY17 reconciliation bill to repeal Obamacare, followed by an FY18 reconciliation bill to pass tax reform. A budget reconciliation strategy was pursued since nearly all Democrats were expected to oppose these policies, making a filibuster threat insurmountable due to the 60-vote requirement.

An FY17 budget resolution that included reconciliation instructions for health care reform was passed by the Senate by a 51-48 vote on January 12, 2017, and by the House on a 227-198 vote the following day. The House later passed the American Health Care Act of 2017 as the FY17 budget reconciliation bill by a vote of 217-213 on May 4, 2017. In July, the Senate Parliamentarian ruled that certain provisions of the House bill must be stricken (as "extraneous" non-budgetary matter) under the Byrd rule before proceeding under reconciliation. The Parliamentarian later ruled that an FY17 reconciliation bill must be adopted by end of FY17, establishing a September 30th deadline. Senate Republicans were unable to obtain 51 votes for any health care reconciliation bill before the deadline, and the FY17 budget resolution expired.

An FY18 budget resolution that included reconciliation instructions for tax reform was passed by the Senate by a 51-49 vote on October 19, 2017, and by the House on a 216-212 vote on October 26, 2017. It permitted raising the deficit by $1.5 trillion over ten years and opening drilling in the Arctic National Wildlife Refuge, the latter to help secure the eventual vote of Alaska Sen. Lisa Murkowski who voted against FY17 health care reconciliation legislation. The Senate later passed the Tax Cuts and Jobs Act of 2017 (unofficial title) as the FY18 reconciliation bill by a 51-48 vote on December 20, 2017, with final passage by the House on a 224-201 vote later that day. Due to the budget resolution's cap of $1.5 trillion in additional deficits over 10 years, plus Byrd rule limits on adding deficits beyond 10 years, the corporate tax cut provisions were made permanent while many of the individual tax cuts expire after 2025.

Process for limiting or eliminating the filibuster

According to the Supreme Court's ruling in United States v. Ballin (1892), Senate rules can be changed by a simple majority vote. Nevertheless, under current Senate rules, a rule change could itself be filibustered, requiring two-thirds of senators who are present and voting to end debate. (This differs from the usual requirement for three-fifths of sworn senators.)

However, despite this two-thirds requirement being written into the Senate rules, any Senator may attempt to nullify a Senate rule by making a point of order that the rule is unconstitutional or just that the meaning of the rule should not be followed. The presiding officer is generally expected to rule in favor of the rules of the Senate, but any ruling from the chair may be appealed and overturned by a simple majority of Senators. This happened in 2013, when Harry Reid of the Democratic Party made a point of order that "the vote on cloture under rule XXII for all nominations other than for the Supreme Court of the United States is by majority vote." Although there is no simple majority vote provision in the text of rule XXII, Reid's point of order was sustained by a 52-48 vote, and that ruling established a Senate precedent that cloture on nominations other than those for the Supreme Court requires only a simple majority. On April 6, 2017, that precedent was further changed by Mitch McConnell and the Republican majority to include Supreme Court nominations.

Other forms of filibuster

While talking out a measure is the most common form of filibuster in the Senate, other means of delaying and killing legislation are available. Because the Senate routinely conducts business by unanimous consent, one member can create at least some delay by objecting to the request. In some cases, such as considering a bill or resolution on the day it is introduced or brought from the House, the delay can be as long as a day. However, because this is a legislative day, not a calendar day, the majority can mitigate it by briefly adjourning.

In many cases, an objection to a request for unanimous consent will compel a vote. While forcing a single vote may not be an effective delaying tool, the cumulative effect of several votes, which take at least 15 minutes apiece, can be substantial. In addition to objecting to routine requests, senators can force votes through motions to adjourn and through quorum calls. Quorum calls are meant to establish the presence or absence of a constitutional quorum, but senators routinely use them to waste time while waiting for the next speaker to come to the floor or for leaders to negotiate off the floor. In those cases, a senator asks for unanimous consent to dispense with the quorum call. If another senator objects, the clerk must continue to call the roll of senators, just as they would with a vote. If a call shows no quorum, the minority can force another vote by moving to request or compel the attendance of absent senators. Finally, senators can force votes by moving to adjourn, or by raising specious points of order and appealing the ruling of the chair.

The most effective methods of delay are those that force the majority to invoke cloture multiple times on the same measure. The most common example is to filibuster the motion to proceed to a bill, then filibuster the bill itself. This forces the majority to go through the entire cloture process twice in a row. If, as is common, the majority seeks to pass a substitute amendment to the bill, a further cloture procedure is needed for the amendment.

The Senate is particularly vulnerable to serial cloture votes when it and the House have passed different versions of the same bill and want to go to conference (i.e., appoint a special committee of both chambers to merge the bills). Normally, the majority asks for unanimous consent to:

• Insist on its amendment(s), or disagree with the House's amendments
• Request, or agree to, a conference
• Authorize the presiding officer to appoint members of the special committee

If the minority objects, those motions are debatable (and therefore subject to a filibuster) and divisible (meaning the minority can force them to be debated, and filibustered, separately). Additionally, after the first two motions pass, but before the third does, senators can offer an unlimited number of motions to give the special committee members non-binding instructions, which are themselves debatable, amendable, and divisible. As a result, a determined minority can cause a great deal of delay before a conference.

Longest filibusters

Below is a table of the ten longest filibusters to take place in the United States Senate since 1900.

Longest filibusters in the U.S. Senate since 1900
	Senator	Date (began)	Measure	Hours & minutes
011	ThurmondStrom Thurmond (D-SC)	August 28, 1957	Civil Rights Act of 1957	24:18
022	DAmatoAlfonse D'Amato (R-NY)	October 17, 1986	Defense Authorization Act (1987), amendment	23:30
033	MorseWayne Morse (I-OR)	April 24, 1953	Submerged Lands Act (1953)	22:26
044	CruzTed Cruz (R-TX)	September 24, 2013	Continuing Appropriations Act (2014)	21:18
055	LaFolletteRobert M. La Follette, Sr. (R-WI)	May 29, 1908	Aldrich–Vreeland Act (1908)	18:23
066	ProxmireWilliam Proxmire (D-WI)	September 28, 1981	Debt ceiling increase (1981)	16:12
077	LongHuey Long (D-LA)	June 12, 1935	National Industrial Recovery Act (1933), amendment	15:30
8	MerkleyJeff Merkley (D-OR)	April 4, 2017	Neil Gorsuch Supreme Court confirmation	15:28
9	DAmatoAlfonse D'Amato (R-NY)	October 5, 1992	Revenue Act (1992), amendment	15:14
1010	MurphyChris Murphy (D-CT)	June 15, 2016	Nominally H.R. 2578; supporting gun control measures	14:50

See also

• Blue slip
• Mr. Smith Goes to Washington, a 1939 film in which a filibuster is a major plot element
• Senate hold
• Senatorial courtesy
• Reconciliation (United States Congress)