Herb Kohl (D-Wis.), left, and Joe Lieberman (I-Conn.), shown in 2001, are… (Hillery Smith Garrison,…)
PEWAUKEE, Wis. — Former Wisconsin Gov. Tommy Thompson won a four-way Republican primary for an open Senate seat Tuesday, setting up an ideologically divisive November battle with Democratic Rep. Tammy Baldwin.
Baldwin, who faced no primary opposition, is the first openly gay candidate to run on a major-party ticket for the Senate. If she wins, she would be its first openly gay member.
Thompson declared victory shortly before 11 p.m., telling cheering supporters gathered at a hotel in this Milwaukee suburb that "Wisconsin is on a roll" — a reference to the political star power of Republican Gov. Scott Walker and the newly selected GOP vice presidential choice, Rep. Paul D. Ryan of Janesville.
According to unofficial returns, Thompson led his nearest rival, Eric Hovde, by about 20,000 votes with 95% of precincts reporting. His rivals conceded.
Thompson, 70, was known during his four terms as governor for his ability to work with Democrats, but he tacked far to the right in the primary in hopes of swaying tea party Republicans.
Baldwin, 50, a veteran U.S. representative from Madison, owns a liberal voting record but in past elections has won over voters in some conservative parts of her district. Her presence on the November ballot is sure to elevate the race into a national showcase.
Even before the primary vote was tallied, Republicans were lining up to paint her as a big-spending and out-of-touch liberal. "Baldwin is far to the left of not just President Obama, but to the vast majority of voters in Wisconsin," read a statement from the National Republican Senatorial Committee.
That may seem a risky calculus for Democrats hoping to retain control of the Senate, a crucial piece of which would be holding onto the Wisconsin seat held for a generation by retiring Democrat Herb Kohl.
Recent polls show Baldwin holding her own in hypothetical matchups with Thompson and the GOP candidates he defeated.
The Senate race will cap quite a year in the national spotlight for Wisconsin politics, beginning with a bruising but failed attempt by Democrats and organized labor to recall Walker.
Thompson served as governor from 1987 to 2001, amassing a broad wellspring of popularity that he clearly hoped would carry over into the Senate campaign. To woo conservatives, he stressed his authorship of landmark welfare-to-work legislation in Wisconsin, which later served as a template for a national welfare overhaul under the Clinton administration.
After his stint in the state capital, Thompson became Health and Human Services secretary for President George W. Bush.
To certify his conservative credentials for the Senate race, Thompson pledged to deliver the decisive vote to repeal Obama's healthcare legislation. His campaign gathered endorsements from icons of the right, including former Defense Secretary Donald H. Rumsfeld, and highlighted support from conservative rocker Ted Nugent, Ohio activist and current congressional candidate Samuel Joseph Wurzelbacher — best known as "Joe the Plumber" — and onetime presidential contender Herman Cain.
Elsewhere, Rep. Connie Mack IV won the Florida Republican primary and will take on Democratic Sen. Bill Nelson in what will be one of the most hotly contested Senate races of the year.
Mack, a four-term congressman who is married to Rep. Mary Bono Mack (R-Palm Springs), handily defeated retired Army Col. Mike McCalister and former Rep. Dave Weldon.
Mack and Nelson will proceed to a general election that, by many measures, is already underway. Nearly $9 million has already been spent by the candidates alone — most of it by Nelson's campaign — and that doesn't count the ad war that began earlier this month, when Nelson went up with a spot that drew an immediate rebuttal ad from Mack.
In Connecticut, Linda McMahon, a former chief executive of World Wrestling Entertainment, won the Republican Senate primary and will face Democratic Rep. Christopher S. Murphy in the race to replace retiring independent Sen. Joe Lieberman.
McMahon easily defeated former Rep. Chris Shays in the primary after spending at least $12 million, much of it from her own pocket. She spent $50 million of her personal wealth on a failed 2010 Senate bid and is expected to pour more millions into the race against Murphy.
Secter, reporting from Wisconsin, writes for the Chicago Tribune. Geiger reported from Washington.