I haven't been following this race very closely, but can someone please explain why the racist counties that Jindal lost in 2003, voted for him now?
Because he wasn't running against a racist scum being this time around.
Well, I personally suspect that might have realized that voting for Blanco was a mistake, and that their vote this time was kind of like a "redo". Also, Jindal campaigned heavily in these areas, I wouldn't underestimate that.
Most probably so. Still, the core of the explanation is that Blanco had an appeal in Northern Louisiana that the current bunch lacked. I've also just spent the past few minutes comparing this election with the 2004 Senate election. Very enlightening, I gotta say. (And Jindal still did notably worse than Vitter in Northern Louisiana.)
Check out La Salle, home of the Jena 6.