THE FILIBUSTER

The filibuster has been part of America's system of checks and balances and has helped promote cooperation and compromise for more than 200 years. Senators have kept the filibuster rules in place to help prevent the dangers of one-party control and to help protect the rights of the minority party. The filibuster is not just a tool of the Democratic party. In fact, in its 200-year history the filibuster has been used by both parties.

From People for the American Way (pfaw.org):
About the filibuster and the "nuclear option"
General filibuster information
A tool used by both parties
An opinion about the misrepresentations of the filibuster