Definition: According to the
US Senate website , the word filibuster -- derived from a Dutch word meaning "pirate" -- was first used more than 150 years ago to describe "efforts to hold the Senate floor in order to prevent action on a bill."
Rule 22
The filibuster is related to "cloture," a rule adopted almost 100 years ago two-thirds vote. At times this was two-thirds of those voting; for a limited time, it was two-thirds of membership.
In 1975, the Senate reduced the number of votes needed to invoke cloture to three-fifths (60) of Senate membership. At the same time, they made the filibuster "invisible" by requiring only that 41 Senators state that they intend to filibuster; critics say this makes the modern filibuster "painless."
Rule 22
The filibuster is related to "cloture," a rule adopted almost 100 years ago two-thirds vote. At times this was two-thirds of those voting; for a limited time, it was two-thirds of membership.
In 1975, the Senate reduced the number of votes needed to invoke cloture to three-fifths (60) of Senate membership. At the same time, they made the filibuster "invisible" by requiring only that 41 Senators state that they intend to filibuster; critics say this makes the modern filibuster "painless."

