What Is a Filibuster in the US Senate?

Senators looking at graph of filibusters during the Obama administration
Senate Democrats Pass 'Nuclear Option' On Filibuster Rules. Win McNamee/Getty Images

 A filibuster is a delaying tactic used in the United States Senate to block a bill, amendment, resolution or other measure being considered by preventing it from coming to final vote on passage.

Filibusters can happen only in the Senate, because the chamber’s rules of debate place very few limits on Senators’ rights and opportunities in the legislative process.

Specifically, once a Senator has been recognized by the presiding officer to speak on the floor that Senator is allowed to speak for as long as he or she wishes.

The term “filibuster” comes from the Spanish word filibustero, which came to Spanish from the Dutch word vrijbuiter, a “pirate” or “robber.” In the 1850s, the Spanish word filibustero was used to refer to American soldiers of fortune that traveled Central America and the Spanish West Indies stirring up rebellions.

The word was first used in Congress in the 1850s, when a debate lasted so long that a disgruntled senator called the delaying speakers a pack of filibusteros.

Filibusters cannot happen in the House of Representatives because House rules require specific time limits on debates.

In addition, filibusters on bill being considered under the federal budgetbudget reconciliation” process are not allowed.

Ending a Filibuster: The Cloture Motion

Under Senate Rule 22, the only way opposing Senators can stop a filibuster is to gain passage of a resolution known as a “cloture” motion, which requires a three-fifths majority vote (normally 60 of 100 votes) of the Senators present and voting.

Stopping a filibuster through passage of a cloture motion is not as easy or as quick it sounds. First, at least 16 Senators must get together to present the cloture motion for consideration. Then, the Senate typically does not vote on cloture motions until the second day of the session after the motion was made.

Even after a cloture motion is passed and the filibuster ends, an additional 30 hours of debate is usually allowed on the bill or measure in question.

Moreover, the Congressional Research Service has reported that over the years, most bills lacking clear support from both political parties may face at least two filibusters before the Senate votes on final passage of the bill: 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.

When originally adopted in 1917, Senate Rule 22 required that a cloture motion to end debate needed a two-thirds “supermajority” vote (normally 67 votes) to pass. Over the next 50 years, cloture motions usually failed to garner the 67 votes needed to pass. Finally in 1975, the Senate amended Rule 22  to require the current three-fifths or 60 votes for passage.

Note that on November 21, 2013, the Senate voted to require a simple majority vote (normally 51 votes) to pass cloture motions ending filibusters on presidential nominations for executive branch positions, including Cabinet secretary posts, and lower federal court judgeships only. Backed by Senate Democrats, who held a majority in the Senate at the time, the amendment to Rule 22 became known as the “nuclear option.”

Cloture motions related to filibusters of Supreme Court nominations continue to require a three-fifths majority vote for passage.

Origins of the Filibuster

In the early days of Congress, filibusters were allowed in both the Senate and the House. However, as the number of representatives grew though the process of apportionment, the leaders of the House realized that in order to deal with bills in a timely manner, House rules had to be amended to limit time allowed for debate. In the smaller Senate, however, unlimited debate has continued based on the chamber's belief that all senators should have the right to speaks as long as they wish on any issue being considered by the full Senate.

While the popular 1939 movie “Mr. Smith Goes to Washington,” starring Jimmy Stewart as Senator Jefferson Smith taught many Americans about filibusters, history has provided some even more impactful real-life filibusters.

In the 1930s, Senator Huey P. Long of Louisiana launched a number of memorable filibusters against banking bills he felt favored the rich over the poor. During one of his filibusters in 1933, Sen. Long held the floor for 15 straight hours, during which he often entertained spectators and other Senators alike by reciting Shakespeare and reading his favorite recipes for Louisiana-style “pot-likker” dishes.

South Carolina’s J. Strom Thurmond highlighted his 48 years in the Senate by conducting the longest solo filibuster in history by speaking for a staggering 24 hours and 18 minutes, nonstop, against the Civil Rights Act of 1957.