You'd struggle to imagine a less inspiring U.S. Senate candidate than Tommy Thompson. Last election won: 1998! Last office held: HHS Secretary! Last election: Hideously misguided 2008 presidential bid! Age on election day: 71!
And lo and behold, PPP finds him doing just fine in Wisconsin.
Feingold, who doesn't seem terribly interested in running, would still be the strongest potential candidate. He has the best favorability rating of anyone we looked at both overall (49/43) and specifically with independents (52/37). He would have the slightest advantage over Thompson, 48-47, and a more healthy one over Neumann at 51-44. Feingold led them by 10 and 12 points respectively when PPP first looked at this race in May so there's been a good amount of movement toward the Republicans since that time.
Voters in the state are pretty evenly divided in their feelings about Thompson with 44% rating him favorably and 42% unfavorably. He would start out with decent sized leads over all the Democratic candidates not named Russ Feingold- 7 points over Ron Kind at 48-41, 8 over Tammy Baldwin at 50-42, and 8 over Steve Kagen at 49-41. Thompson was tied with Kind, led Baldwin by only 1, and had just a 3 point advantage over Kagen the last time we polled so again these numbers show momentum in the GOP's direction.
He's still got it!
There's not really any 2012 scenario wherein Democrats lose Wisconsin and hold the Senate.