Tommy could be a transitional figure, someone to keep it out of the hands of ‘Rats for one or two terms, at which point a younger and more consistantly conservative Republican with name I.D. can move in after he retires.
With Rusty out, I think any Republican of credibility can take the seat (’cept Neumann, he needs to stay out). Why wait 6-12 years to get another Ron Johnson type ? As I said before, Tommy passed up multiple opportunities when he was younger to take out Rusty and Kohl and he ought not be rewarded for his failure to step up. I applied the same thing to Lamar! who failed to step up in 1984 to stop Gore.