David Prosser tells a story of how he intervened to protect the state Capitol's custodial staff. It happened during the week of Feb. 20, when the building was packed with people protesting Gov. Scott Walker's anti-union agenda.

"Working in the building, the noise has just been deafening," says Prosser, since 1998 a Wisconsin Supreme Court justice. And so, when a custodian he knows well came into his chamber, he asked her, "Do you have earplugs?" She didn't.

"I think you need earplugs," Prosser responded, noting that these were being worn by law enforcement officers throughout the building. "I went down to the police and said, 'You have got to give custodians at least the opportunity to wear earplugs.' It was done within the hour."

It's a little story of little import, other than that Prosser is a considerate guy. But it was one of the only times in a 90-minute interview at Isthmus last week that Prosser was willing to stake out a position - it's too loud - on issues almost everyone else is taking sides on, and which will surely play a pivotal role in his bid for reelection to a 10-year term against challenger JoAnne Kloppenburg.

"Two weeks ago, Prosser looked like he had a commanding lead," reflects Mike McCabe of Wisconsin Democracy Campaign. "Now this race has been made into a referendum on Scott Walker."

Prosser, an appointee of Gov. Tommy Thompson who was reelected without challenge in 2001, agrees this is happening, and he doesn't like it one bit: "They don't want to vote against my record; they want to vote against Scott Walker."

But even Prosser's supporters cast the April 5 election in partisan terms, seeing it as integral to Walker's determination to transform Wisconsin.

"David Prosser is the only conservative running in the state Supreme Court race," declares a recent web post from the Wauwatosa Republicans. "If he doesn't win, the court will have a 4-3 liberal majority, and all of the reforms that Governor Walker is accomplishing will be challenged and judged by liberal legal activists who believe that their opinions are more powerful than the Constitution. Please don't let that happen. Volunteer to help."

It's no mystery why the crisis in the Capitol has added urgency to the high court race. Prosser, 68, came up through the political ranks as a Republican district attorney, congressional aide and member of the state Assembly. Should he lose the election, the court's conservative majority - variously placed at 4-3 or 5-2 - could be eroded at a critical time.

Kloppenburg, 57, a longtime assistant attorney general, wants to capitalize on this moment without claiming partisan ground.

"I'm running to restore people's confidence," she says. "I will preserve the role of the court as a coequal and independent branch of government that serves as a check and balance on overreaching by the executive and legislative branches." She adds, "What's happened in the last three weeks has brought that home."

Does that mean Kloppenburg thinks there has been overreaching by the governor and Legislature? Here she hits the brakes.

"I think, ah...." Ten-second pause. "That can't be determined yet. We don't know if there's overreaching until you have a law, and there has been no law."

What about the budget repair bill and biennial budget in their current form: Any signs of overreaching there?

In the absence of a particular case that is brought before the court, says Kloppenburg, "I can't speculate on that."

Ray Dall'Osto, a Milwaukee attorney who handles criminal and civil cases and is considered an expert in constitutional law, agrees the role of the Supreme Court is magnified by recent events, as is the importance of the upcoming election.

"Our whole system of government is built on laws, and we're seeing this upended," says Dall'Osto, who in the late 1970s and early 1980s was legal director of the Wisconsin ACLU. "This is creating a critical tension in this state."

Among the issues of the moment that Dall'Osto thinks could end up before the Supreme Court:

Are the restrictions imposed on access to the state Capitol legal? It's been argued that these violated the Wisconsin Constitution, the state's open meetings law, and a statute requiring access to court proceedings (including the Supreme Court, which was in session last week while citizens were being denied entry). A Dane County judge deemed the state's restrictions unconstitutional, but disputes over access will not likely end there.

Does the governor's attempt to revoke the collective bargaining rights of some public employees but not others violate the equal protection clause of the U.S. Constitution?

Can the governor and Legislature impose what Dall'Osto calls "gross limitations on local powers," demanding that they freeze property taxes at the same time as state funding for schools and local services is slashed?

Can these local governments ignore existing contracts with public employee unions in order to balance their budgets? Dall'Osto says the Walker team seems to be "taking the position of treaties with Indian tribes: They're good the day they're signed, and then we can just abrogate them."

Despite the supreme relevance of these issues, the candidates are reluctant - perhaps appropriately so - to comment on them.

For instance, when asked last week about the restrictions to state Capitol access, Prosser replied, "It would be extremely ill-advised for me to comment on something that could literally be before the court in a couple of days." (Prosser, by the way, was "completely shocked" to learn during his March 3 Isthmus interview that former U.S. Congressman David Obey was barred from entering the building the day before. The justice says he doesn't watch the news.)

Here's Kloppenburg on this same issue: "It does concern me as a citizen that a public building was closed to the public. But whether that was unlawful is not something I can say."

Kloppenburg does find fault with the process, saying there should be "a dialogue and discussions, hearing each other out" within all branches of government. "What's going on here [at the Capitol] is in part a reaction to the fact that no discussion took place, that there has been no listening."

Asked specifically about Walker's call to extract unilateral concessions and strip away collective bargaining rights, Kloppenburg says, "Whether it is overreaching is unclear until a case is brought and it comes to the court. But what troubles them [the workers and other protesters] is the process - that they've just gone ahead and done this without engaging."

Prosser puts it like this: "It's imperative that the state get its fiscal house in order [and] send a message that this is a great place to do business. [And] it would seem to me that the governor makes his strongest case when he can show a linear relationship between the proposal he makes and our fiscal situation. To the extent he is unable to do that, he begins to lose public support."

He continues, "I had no forewarning of anything the governor proposed. I don't necessarily agree with some of the things that he's proposed. But I may have to rule on them at some point, so I don't think it is really appropriate for me to weigh in on his strategy or tactics."

Both Kloppenburg and Prosser are in a bind - anything they say that suggests bias in how they'll approach cases can and will be used against them. So both insist they are fair-minded and nonpartisan, while painting each other as ideologues.

"If you look at her political contributions, affiliations, the kinds of cases she's handled, there is a pattern here," says Prosser of his opponent, implying she's an ultra-liberal.

But Prosser's evidence is notably thin, and, by his own admission, not based on anything Kloppenburg has said. He notes that her campaign is run by Melissa Mulliken, who also - gasp! - has managed the campaigns of Kathleen Falk. He finds it "significant" that Kloppenburg endorsed Wisconsin Green Party candidate Ben Manski over Democrat Brett Hulsey in last fall's election. And he claims others have told him, about Kloppenburg, "Here is an unbending ideologue." He won't reveal who these tipsters are.

Kloppenburg, of course, denies this: "I am not running to join any bloc. I am not running to advance any political agenda, be it conservative or liberal or anything else." She says Prosser, in contrast, "has already indicated how he is going to judge cases."

Exhibit A is a Dec. 8 press release in which Prosser's newly hired campaign manager said his reelection was about "protecting the conservative judicial majority and acting as a common sense compliment [sic] to both the new [Walker] administration and [GOP-controlled] Legislature."

Prosser says he didn't approve this release and doesn't agree with it; he vows to "review legislation impartially," upholding whatever is constitutional and in keeping with legislative intent.

A self-described "judicial conservative," Prosser has a 100% rating from the Wisconsin Civil Justice Council, a coalition of state business groups, on its issues of concern, from 2008 through the end of 2010. And clearly, Republicans in the state Legislature feel that David Prosser is one of them.

When the Supreme Court justices were introduced at Walker's State of the State speech and again at his budget speech, Prosser, a former state Assembly speaker, received by far the loudest and most sustained ovation, mostly from the Republican side of the aisle.

Prosser says he's always enjoyed warm relations with the Legislature, sending Christmas cards to the entire body each year since the mid-'70s. "These people are friends of mine," he says, adding that Dems as well as Republicans fill out the ranks of his fan club. "I get along with all of them."

He says this adulation, though gratifying, "doesn't prove I can't be an impartial judge." And while Prosser often aligns with the court's conservatives - Justices Pat Roggensack, Annette Ziegler and Mike Gableman there have been cases where he's sided with Chief Justice Shirley Abrahamson, the court's reigning liberal; he even provided a list of 13 of them, going back to 2000.

"On paper, I have the most partisan background of any member of the court," admits Prosser, who from 1952 to 1998 was an unabashed partisan. But he insists he's outgrown all that, noting that he's backed Abrahamson in past elections and defended her in an internal court dispute in the late 1990s ("I wouldn't do it today because she has changed"). He claims overall to have shown an independent streak on the court.

Yet Prosser's campaign website prominently displays a newspaper editorial that states, "The court is split 4-3, with self-described judicial conservatives, including Prosser, most often in the majority."

And Prosser agrees the court tends to divide in predictable ways. He says he sometimes plays "a game" with his law clerks, asking if they can guess the outcome of the vote just taken in closed session, after oral arguments.

"It is usually not difficult to determine exactly what the vote was," says Prosser. "I suspect on some other courts, the game that I'm talking about would be more difficult."

David T. Prosser Jr.

Age: 68

Bio: Chicago native, raised in Appleton; single; DePauw University and UW Law School grad; former Outagamie County DA, U.S. Justice Department official and congressional aide; state Assembly rep from 1979 to 1996; served briefly on Wisconsin Tax Appeals Commission; appointed to the Supreme Court in 1998; reelected in 2001.

JoAnne Kloppenburg

Age: 57

Bio: Born and raised in Connecticut, in Madison since 1985; husband and three kids; Peace Corps volunteer in Botswana in late 1970s; Yale and UW Law School grad; interned for Shirley Abrahamson and clerked for federal Judge Barbara Crabb; state assistant attorney general since 1989, specializing in environmental issues.