"Even within the political side, what makes sense from the perspective of getting re-elected often doesn't make sense from the perspective of forging a legislative coalition, as the existence of Evan Bayh and Tom Coburn constantly reminds us. (One way to be good at getting re-elected and bad at legislative politics is to undercut your own party in an effort to win over centrist voters. Another way is to energise your base by taking legislative positions so extreme they can't possibly be enacted.)"

-- The Economist "Democracy in America" blog