If you had one thing, and one thing only, to predict which Democratic House incumbents would lose their seats in 2010, what would you take? The amount of money they raised? Their TARP vote? Their health care vote? Whether they had a Tea Party opponent? A Nazi reenactor opponent?
The best predictor by far is none of those. It is simply how Democratic their district is. ... In all 402 contested House elections, the 2008 presidential vote in that district would explain 83% of the variation in the Democratic House candidate's vote share. Nothing else in our dataset comes close.
Focusing on the Democratic incumbents who lost shows how crucial the partisanship of their district was
Campaigns seem to matter much less than how districts are drawn. A comment on this story pointed out how many districts had more than 75% Democrats, and how few had more that 75% Republicans. This seems to indicate successful gerrymandering on the part of Republicans.
