Sen. Herb Kohl's announcement Friday that he won't seek a fifth term put Democrats on the defensive in Wisconsin, a state that swung heavily Republican in 2010 and will be an important part of President Barack Obama's re-election effort.
Kohl's decision came as a surprise to both parties. Just last week, top Democrats in Washington talked about his re-election as if it were a matter of fact. Now, the 76-year-old NBA team owner and department store founder joins four other Democrats who have decided to retire rather than fight to keep their seat. Two Republican senators have also said they won't run again.
Though the number of retirements is not historically high, Kohl's decision to not to run in 2012 further complicates the already tricky task Democrats are facing in their attempt to stay in control of the Senate. Republicans, who already control the House, need to pick up just four new seats to swipe the Senate majority away from Democrats.
Incumbents tend to be favored to win re-election in Senate races, so the retirements give the GOP more of an opportunity to pick up seats. Republicans already had signaled they would run vigorous campaigns in these states.
"I've always believed it's better to leave a job a little too early than a little too late. And that's how I feel today," Kohl said during a Friday news conference in Milwaukee. "The interest and the energy I have for this job will find a new home at the conclusion of this term."
Though no contenders came forward Friday, the race for Kohl's seat will also serve as a good barometer of the political mood in Wisconsin, a swing state that Republicans swept to statewide gains in 2010.
Despite GOP control of the governor's mansion and statehouse, Wisconsin is still seen as up for grabs after it became the national battleground in the fight over union rights. Democrats believe the rancor that provoked tens of thousands to protest Gov. Scott Walker's moves to strip unions of most collective bargaining rights has given them the strength to rebound in 2012.
Six Republican state senators, along with three Democrats, face potential recall elections this summer over their positions on the collective bargaining law. There's also a movement to recall Walker, who just took office in January, but that effort would not begin until later this year.
State Democratic Party Chairman Mike Tate said voters are reacting to what he called the extreme agenda of Republicans and was confident Democrats could keep Kohl's seat at the same time the party deals with a potential Walker recall effort and the presidential race.
"Our job now will be to ensure the seat remains in the hands of a Democrat," Tate said.
Wisconsin was one of 28 states Obama carried in the 2008 presidential election, winning by 14 percentage points, and it would be tough for him to win the White House again in 2012 without its support. Obama has visited Wisconsin seven times since taking office, and until last fall, the state had been trending Democratic.
But the most prominent Democrat who has been mentioned as a potential candidate to replace Kohl, Russ Feingold, lost during last fall's mid-term to a virtually unknown tea party favorite, Ron Johnson. Other possible Democrat contenders include U.S. Reps. Tammy Baldwin, of Madison, and Ron Kind, of La Crosse, and Milwaukee Mayor Tom Barrett.
Baldwin is likely to run, said a person close to her who spoke on condition of anonymity Friday because the congresswoman wanted to keep the day focused on Kohl's retirement. Kind's spokeswoman had no comment on his plans.
Feingold and Barrett, who lost to Walker in the 2010 governor's race, both issued statements praising Kohl but did not address whether they would run for his seat.
Republicans see Kohl's retirement as a clear pickup opportunity.
Wisconsin Attorney General J.B. Van Hollen, a Republican, is considering a run, according to his campaign. And state Assembly Speaker Jeff Fitzgerald would consider running if U.S. Rep. Paul Ryan doesn't get into the race, said Fitzgerald's spokesman John Jagler. Ryan said in a statement that he was surprised by Kohl's announcement and wanted to take some time over the next "few days" to discuss the news with his family and supporters before deciding whether to run for the seat.
Mark Neumann, a former congressman and losing GOP candidate for governor in 2010, also said he is considering running but had no timetable in mind for making a decision. Wisconsin Senate Majority Leader Scott Fitzgerald, the Assembly leader's brother, along with former state Sen. Ted Kanavas and former U.S. Rep. Mark Green are also mentioned as possible candidates.
Kohl, a millionaire and owner of the Milwaukee Bucks, was first elected to the Senate in 1988 and never won an election with less than 52 percent of the vote. Born and raised in Milwaukee, he worked as an investor before founding the Kohl's grocery and department stores that earned him a fortune. He also is widely credited with keeping NBA basketball in the relatively small market of Milwaukee.
He was a reliably liberal Democrat whose unassuming manner was, in some ways, what distinguished him in Wisconsin. The state's senators have a storied, bipartisan history of outspokenness and boisterousness, including Robert La Follette, the famous populist Republican senator, Joseph McCarthy, who famously raged against Communists lurking in the US, Gaylord Nelson, the liberal Democratic senator who helped found Earth Day, and Feingold, the feisty, populist Democrat.
Besides Kohl, Democratic Sens. Kent Conrad of North Dakota, Jim Webb of Virginia, Jeff Bingaman of New Mexico and Daniel Akaka of Hawaii all have announced their retirements, as has Sen. Joe Lieberman, who runs as an independent but caucuses with Democrats.
Republicans face two retirements, both in states that tilt toward Republicans: Sen. Kay Bailey Hutchison announced earlier this year she wouldn't seek re-election in Texas as did Sen. Jon Kyl of Arizona.
Kohl's term ends Jan. 3, 2013.
Jackson reported from Washington. Associated Press writers Todd Richmond in Madison, Wis., and Carrie Antlfinger in Milwaukee contributed to this report.