Today, Herb Kohl of Wisconsin will become the sixth Democratic senator to retire rather than seek another term in 2012. Of those six retirement announcements, this is surely among the more problematic for Democrats.
Though he first won election to the seat by only a narrow margin in 1988, Mr. Kohl has by and large faced only token opposition since then, and won re-election even in 1994, a poor year for Democrats. His approval ratings remained reasonably strong. Though there was a theoretical chance that Republicans might have mounted a vigorous challenge to him in 2012, there was no sign of one actually coming.
Now, though, Mr. Kohl’s retirement throws the race is open to a number of heavyweight names on both sides.
Russ Feingold, the longtime senator who lost the state’s other seat to Ron Johnson last year, would probably be the Democrats’ strongest candidate. His liberal but eccentric track record would appeal both to labor-union voters — who are distressed by the efforts of the Republican governor, Scott Walker, to peel back collective bargaining rights for public employees in the state — and to a national fundraising base of Democratic bloggers and activists.
Mr. Feingold’s approval ratings have remained at tolerable levels even through his defeat by Mr. Johnson, and a Public Policy Polling survey conducted in December found him with modest leads over potential Republican opponents in hypothetical matchups.
Mr. Feingold might have other ideas, though, possibly including running for governor if Democrats succeed in recalling Mr. Walker. If Mr. Feingold stays out of the Senate chase, attention would turn to Democratic members of the state’s House delegation. Of that group, Representative Ron Kind, who survived the Republican tide last year (although against a flawed opponent), would probably have the most statewide appeal; his district is in the western part of the state.
Another Democratic Representative, Tammy Baldwin, who represents the Madison area, is also likely to consider a bid, according to Nathan Gonzales of the Rothenberg Political Report. Ms. Baldwin, who is a lesbian, could become the first openly gay member of the United States Senate.
The most intriguing name on the Republican side is Representative Paul Ryan, who had hinted in the past that he would run for the Senate if Mr. Kohl were to retire. Mr. Ryan, a rising political star from the southeastern corner of the state whose entitlement-slashing budget proposal is the subject of widespread praise among Republicans and equivalent scorn from Democrats, would nationalize the race, and probably draw in tens of millions of dollars in campaign contributions for both sides.
Mr. Ryan, however, would also face some opportunity costs that might discourage him from running. Most notably, winning for him would mean sacrificing his leadership position in the House to become a junior member of the Senate.
If Mr. Ryan has his eyes on national office in 2016 or some other year ahead, there are arguments both for and against seeking the Senate seat. If Mr. Ryan passes this year, it could be some time before he got another opportunity to run for statewide office, and few candidates have mounted serious presidential bids from the House. On the other hand, running and losing would raise questions about his electability and diminish his star power.
(Though Mr. Ryan will probably face a Democratic challenge anyway if he chooses to run for re-election to his House seat instead of trying for the Senate, he has overperformed in his Republican-leaning district in the past and will probably see its safety shored up by the state’s Republican-led redistricting this year.)
Other plausible Republican candidates, according to various reports, include the state Attorney General, J.B. Van Hollen; the Republican National Committee chairman, Reince Priebus; and several of Mr. Ryan’s current and former colleagues in the House. Tommy Thompson, who served four terms as governor, is another possibility, but he declined to run for the Senate last year.
My view is that Democrats are slightly more likely to retain the Senate seat than to lose it, in part because Mr. Feingold faces fewer disincentives to run than Mr. Ryan, and in part because Wisconsin has had a slight Democratic lean in most years. Although Republicans reversed that trend last year, there is some evidence that the labor disputes since then have done more to energize Democratic voters than Republicans. Recall elections later this year could give us a better read on the political climate within the state.
It’s important to remember that the outcome of Senate races in different states are substantially correlated with one another. If Democrats win one toss-up, they will probably tend to win most others, which could allow them to retain control of the Senate even though they must defend more than twice as many seats this time around as the Republicans.
Still, any Democratic advantages in Wisconsin are liable to be slight, as they usually are. And because of the unpredictability over which candidates will run, as well as the volatility of the political climate in the state, this race could march more to its own beat than most others do.
Even in the best case for Democrats, Mr. Kohl’s retirement will require them to spend a lot of money to hold a seat that Mr. Kohl’s personal wealth had allowed them to skimp on in the past.