Sen. Joe Manchin, D-W.Va., who many consider the second-most-powerful politician in the U.S., responded emphatically on Monday when asked if he would ever wavier in his support of the procedural tool known as the filibuster.Earlier this year, Manchin told the Washington Post, "I will not vote to bust the filibuster under any condition, on anything that you can think of." He was joined by Sen. Kyrsten Sinema, D-Ariz., who has said that she is not open to "changing her mind." Manchin’s opinion on the filibuster is important because the Senate is evenly split 50-50, with the deciding vote going to Vice President Harris. In most legislation, there needs to be a 60-vote threshold to advance most legislation to President Biden’s desk. Progressive Democrats see the filibuster as an outdated relic that can be used by the minority Republican Party under McConnell to derail Biden’s agenda, and they want to do away with it. They point to the way the filibuster was wielded during the 20th century to stall civil rights legislation, and warn of a repeat.