From "No way to run a democracy" in the Sept 16th edition of The Economist:
http://www.economist.com/opinion/displayStory.cfm?story_id=3196241
A different article in the same magazine says that there were an average of 100 close races in 1992-6 and 50 in 2000-02.
CBL
Here is a link but I think you need to be a subscriber:The other great blot on American democracy—redistricting—has already made a nonsense of elections to Congress. Despite all the hoopla about the 50:50 nation, no more than around 30 seats of the 435 in the House of Representatives are competitive (see article). In 2002, four out of five congressmen won their races by more than 20 points. This is because most states allow their politicians to determine the boundaries. The result is gerrymandering on a grotesque scale, with incumbents stitching up safe seats by drawing absurd districts that look like doughnuts, sandwiches and Rorschach tests.
This is not just unfair; it puts people off voting (why bother in those 400 districts where the result is a foregone conclusion?) and it drives politics to the extremes. With no chance of being unseated by the other party, a congressman's only threat is the partisans in the primary; so Republicans become ever more conservative and Democrats ever more left-wing.
http://www.economist.com/opinion/displayStory.cfm?story_id=3196241
A different article in the same magazine says that there were an average of 100 close races in 1992-6 and 50 in 2000-02.
CBL