Last Friday, Wisconsin Democrat Herb Kohl (of the Kohl's Department Store fortune) announced he is retiring from the Senate, and will not run for re-election in 2012. Richard Baehr notes that he has had health problems, but was likely to have been re-elected, had he run. Russ Feingold, who was defeated by Ron Johnson in 2010, by a 5% margin, was speculated about as a candidate for Kohl's seat in 2012, a presidential election year that could spark higher turnout among Democrats. But his former chief of staff issued a statement last week saying that "Running for office in 2012 is not something Russ is eager to do or has been planning to do."
Today comes news that Tommy Thompson, former popular four-term Republican governor, has told friends that he plans to run for the Senate in 2012. There had been speculation that Paul Ryan would run for the Senate, but Ryan has announced he will stay in the House and keep his accumulated seniority.
Thompson has to be reckoned a powerful candidate in Wisconsin, and we can expect this race to generate a lot of national attention.
Update: Richard Baehr rates a Thompson-Feingold Senate race as a 50-50 chance for a pickup, noting that Thompson is 69, and has been out of office for a long time.