http://fivethirtyeight.com/datalab/senate-update-whats-the-matter-with-south-dakota/"Yet another complication is that Pressler has refused to say who he’ll caucus with. Our ideology ratings imply that he’s equivalent to a moderate Republican — just as they imply that Orman is equivalent to a moderate Democrat. So the model assumes there’s a 75 percent chance Pressler would caucus with Republicans if he wins, just as it assumes there’s a 75 percent chance Orman would caucus with Democrats. But Pressler endorsed Barack Obama in both 2008 and 2012 and has at times implied that he’d refuse to caucus with anybody.
Rounds remains the favorite. It’s not clear that Pressler has enough money to run a substantial number of advertisements in the closing days of the campaign — or to finance a voter turnout operation. And for the time being, the SurveyUSA poll is mostly alone."
