Filibuster in the United States Senate

Filibuster is a tactic used in the United States Senate to prevent a measure from being brought to a vote by means of obstruction. The most common form occurs when one or more senators attempt 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"[1] (currently 60 out of 100) vote to bring the debate to a close by invoking cloture under Senate Rule XXII
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At times, the "nuclear option" has been proposed to eliminate the 60 vote threshold for certain matters before the Senate. The nuclear option is a parliamentary procedure that allows the United States Senate to override a standing rule of the Senate, including the 60-vote rule to close debate, by a simple majority of 51 votes, rather than the two-thirds supermajority normally required to amend the rules.

https://en.wikipedia.org/wiki/Nuclear_option