Tommy Thompson should have run in 2004, when his chances of winning were at least 50/50. He was right not to run in 2006 though, when a liberal perfect storm swept the northern tier states.
Frankly, even ‘04 was a bit too late. He should’ve run in ‘94 (against Kohl) or ‘98 (Feingold), with 2000 at the latest. At this point, he’d be treating the place as a retirement home and we need younger blood. Hell, he should’ve been retiring from the Senate at this point.