Filibusters and cloture are two important concepts in the United States Senate that play a crucial role in shaping the legislative process. A filibuster is a tactic used by Senators to prolong debate on a bill or nomination, effectively preventing it from being brought to a vote. This can be done by a single Senator or a group of Senators who oppose the measure and wish to delay its passage or kill it altogether.

Cloture, on the other hand, is a procedure that allows the Senate to limit further debate on a bill or nomination, effectively ending a filibuster. To invoke cloture, a majority of Senators must vote in favor of a motion to proceed, which limits further debate to a set amount of time. If the cloture motion fails, the filibuster continues, and the bill or nomination remains stalled.

The use of filibusters has been controversial throughout history, with some arguing that they allow for thorough consideration of important legislation and others claiming that they obstruct the will of the majority. The cloture rule was introduced in 1917 as a way to address this issue, but it has also been subject to criticism, with some arguing that it restricts the ability of minority voices to be heard. Despite these criticisms, both filibusters and cloture remain integral parts of the Senate's rules and procedures, and their use continues to shape the course of legislative debates.