<Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> 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 . </P> <P> 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 . </P> <P> 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 . </P>

When did the filibuster start in the us senate