Actually, it’s not so clear. The Governor would get to make a two-year appointment if Bayh had to resign his seat, with a Special Election to be held in 2010. The present governor of Indiana is Mitch Daniels, a Republican. Unlike some states — Arizona, for instance — Indiana does not appear to have any requirement wherein a gubernatorial appointee must pick a candidate from the departing Senator’s party.
But would Daniels still be Governor at the time Bayh resigned his seat? He’s in a quasi-competitive race with Jill Long-Thompson. I’m not entirely sure how Indiana elections law works — this is one of those instances where Google fails you –but I’d assume as a default that the incoming Governor would get to make the appointment (there’s only a 49.99 percent chance that I’m wrong about this). If this whole parlay plays out, you could have a two-birds-with-one-stone, de facto Senate race in Indiana based on the gubernatorial result.
In any event, we have a very boring set of gubernatorial races this year, but Indiana is one that the Democrats ought to consider pouring some money into (and Republicans likewise to defend their incumbent). It’s a state that has long been redder than it “should” be based on its demographics, and where there might be some long-run benefits to building out the party’s infrastructure.