Indiana Democratic Rep. Joe Donnelly is getting into the Senate race. Donnelly is probably the strongest candidate Democrats could muster for that seat. There's no way he'd be running if Lugar was his likely opponent, because Lugar, a popular moderate, would mop the floor with Donnelly. But Lugar is very unlikely to survive a right-wing primary challenge, and the opportunity to run against non-incumbent Tea Party Republican Richard Mourdock creates a real opportunity for a pretty strong candidate like Donnelly.