Filibuster

A filibuster is a tactic used in the U.S. Senate to delay or block a vote on a measure by preventing debate on it from ending.[1] The Senate's rules place few restrictions on debate; in general, if no other senator is speaking, a senator who seeks recognition is entitled to speak for as long as they wish.[2] Only when debate concludes can the measure be put to a vote. Rule XXII of the Standing Rules of the Senate allows the Senate to vote to end a filibuster by invoking cloture on the pending question. In most cases, however, this requires a majority of three-fifths of senators duly chosen and sworn. https://en.wikipedia.org/wiki/Filibuster_in_the_United_States_Senate

Only a small number of supermajority requirements were explicitly included in the original U.S. Constitution, including conviction on impeachment (two-thirds of senators present),[20] agreeing to a resolution of advice and consent to ratification of a treaty (two-thirds of senators present),[21] expelling a member of Congress (two-thirds of members voting in the house in question),[22] overriding presidential vetoes (two-thirds of members voting of both houses),[23] and proposing constitutional amendments (two-thirds of members voting of both houses),[24] Through negative textual implication, the Constitution also gives a simple majority the power to set procedural rules:[25] "Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behaviour, and, with the Concurrence of two thirds, expel a Member."[22] In Federalist No. 22, Alexander Hamilton described super-majority requirements as being one of the main problems with the previous Articles of Confederation, and identified several evils which would result from such a requirement... In 1789, the first U.S. Senate adopted rules that did not provide for a cloture mechanism, which opened the door to filibusters. Indeed, a filibuster took place at the very first session of the Senate... In 1917, during World War I, at the urging of President Woodrow Wilson,[33] the Senate adopted a rule by a vote of 76–3 to permit an end to debate on a measure in the form of cloture.[34] This took place after a group of 12 anti-war senators managed to kill a bill that would have allowed Wilson to arm merchant vessels in the face of unrestricted German submarine warfare.

After a series of filibusters in the 1960s over civil rights legislation, the Senate put a "two-track system" into place in 1972 under the leadership of Democratic Majority Leader Mike Mansfield and Democratic Majority Whip Robert Byrd. Before this system was introduced, a filibuster would stop the Senate from moving on to any other legislative activity. Tracking allows the majority leader—with unanimous consent or the agreement of the minority leader—to have more than one main motion pending on the floor as unfinished business. Under the two-track system, the Senate can have two or more pieces of legislation or nominations pending on the floor simultaneously by designating specific periods during the day when each one will be considered.

In 2005, a group of Republican senators led by Majority Leader Bill Frist proposed having the presiding officer, Vice President Dick Cheney, rule that a filibuster on judicial nominees was unconstitutional, as it was inconsistent with the President's power to name judges with the advice and consent of a simple majority of senators.