How much will "birthers" affect 2010 in the Senate?

If you look at 5 major candidates for U.S. Senate, maybe quite bit,

Money quote

"Several of these candidates have later corrected their initial hesitation, but it is precisely that initial hesitation that contains so much information about what Republican candidates fear right now. No doubt that Portman and Marco Rubio know that Birtherism is bullshit. The gap between their private beliefs and how they articulate them publicly is fairly wide. I'm not a fan of stories that begin with X 'refuses to denounce' Y -- I usually skip them. I make an exception here because the accusation is so reckless, so tied to race and culture, and so stupid that those who try to Wink at the Birthers are adding potency to a poison that everyone is forced to gulp."