Whips are assistants to the floor leaders in Congress who are also elected by their party conferences. The Majority and Minority Whips (and their assistants) are responsible for mobilizing votes within their political parties on major issues. In the absence of a party floor leader, the whip often serves as acting floor leader.
In the 110th Congress (2007-2009), the majority (Democratic) whip in the Senate is Senator Richard Durbin from Illinois, and the minority (Republican) whip is Kentucky Senator Mitch McConnell. In the House, the whips are Representative James Clyburn from South Carolina for the Democrats, and Representative Roy Blunt of Missouri for the Republicans.