Tactic of delaying action on a bill by talking long enough to wear down the majority in order to win concessions or force withdrawal of the bill.
The tactic is normally employed by a group that cannot muster enough votes to defeat a bill by vote. Filibustering is possible in the U.S. Senate because Senate rules allow unlimited debate on a bill. A filibuster may be carried out by a group or a single member, and the speech need not be related to the bill under discussion. Calling for a vote to limit debate (cloture)
which requires 60 votes, the votes of three-fifths of the entire membership, in the U.S. Senate
or holding around-the-clock sessions to tire the speakers are measures used to defeat filibusters.