A filibuster is a process senators use to block measures or legislation. It is a parliamentary tactic. For a filibuster to be stopped 60 votes are required. It has recently been used by Democrats to block judicial nominees of President Bush where the nominees were though to be too conservative, or lacked impartiality due to their personal beliefs. They use the filibuster to prevent a vote on the nominees.
"Use of the term filibuster began to appear in the 1840s. It is derived from the Dutch word vrijbuiter, or free booter, and the Spanish filibustero. Both terms refer to pirates. The filibuster was used in the 1950s and 1960s to impede civil rights legislation. In 1957 Strom Thurmond launched the longest one-man filibuster in history, speaking for more than 24 hours to block the Civil Rights Act of 1957." See http://www.cnn.com/2005/POLITICS/05/04/filibuster.fight.q.a.ap/index.html
