A filibuster is a legislative tactic used in the U.S. Senate to delay or block a vote on a bill by extending debate. Senators can speak for as long as they wish on any topic unless 60 members vote to end debate through a cloture motion. This practice allows the minority party to exert influence over legislation and encourages prolonged discussion on important issues. Critics argue that it hinders prompt governance and can lead to legislative gridlock, while proponents believe it protects minority interests and promotes thorough examination of proposed laws.