See Amendments 9, 10
http://blog.heritage.org/2010/02/02/can-u-s-senators-be-recalled/
http://www.freerepublic.com/focus/news/2391820/posts?page=1
The recall of members of the U.S. Congress has never been permissible according to the Constitution, and no member of the Congress has ever been removed by such means. That’s because the U.S. Constitution sets the qualifications and terms for being a member of the House or Senate; changing those qualifications or terms (as in making them subject to a recall) is unconstitutional and would require a constitutional amendment.
The Constitution contains an expulsion clause for members of Congress, though it has widely been neglected since the Civil War cases of disloyalty. The most effective means of removal is still election: if a member of Congress does not do their work well, then don’t return them to office.