In Tuesday’s primary, West Virginia Democrats booted 14-term Rep. Alan Mollohan by a wide margin. That follows Utah Republicans denying Sen. Robert Bennett a spot on their primary ballot for a fourth term. How endangered are incumbents in both parties? Are Senators Arlen Specter and Blanche Lincoln in big trouble in next week’s primaries? Could booting the incumbents now actually improve the parties’ chances of holding those seats? We ask Larry Sabato, director of the Center for Politics at the University of Virginia.