HELENA — A nonpartisan race for Montana Supreme Court has taken a distinctly partisan edge, with challenger Lawrence VanDyke trying to cast Justice Mike Wheat as a liberal activist judge as his Republican backers pour tens of thousands of dollars into ads to support that message.

Wheat and his supporters, in turn, have taken to the airwaves with their own ads, leading to a money battle in an election that is usually considered an afterthought on the ballot.

The battle is a sad sign that the U.S. Supreme Court’s 2010 Citizens United decision that allowed increased corporate spending in federal elections has arrived at the state’s down-ticket races, Wheat said.

“Our court system is under attack from out-of-state money,” Wheat said in a recent interview with The Associated Press. “When it’s over, I guess they will spend somewhere around $1 million. Why in the heck would they do that? Because they want a court that is not fair and balanced, a court that is going to make decisions more to their liking.”

Wheat is campaigning to keep the seat he was appointed to in 2010 by then-Gov. Brian Schweitzer. He has been an attorney since 1978 and served on the state Legislature for two terms as a Democrat.

VanDyke was the state’s solicitor general for about 1 1/2 years under Republican Attorney General Tim Fox. He previously worked for the law firm Gibson, Dunn and Crutcher in Texas and was a clerk for federal appellate Judge Janice Rogers Brown.

Judicial candidates in Montana aren’t allowed to label themselves as a member of a political party. A federal court ruled last year that parties may endorse judicial candidates, but the candidates themselves may not use those endorsements in their campaigns.

So VanDyke has focused on Wheat’s legislative past, saying Wheat “judges like a Democrat.” Wheat and other current Supreme Court justices are “results-oriented” judges who attempt to legislate from the bench, VanDyke said.

“I think Montana judges generally try very hard to follow the law,” VanDyke said in a recent interview with The Associated Press. “But I do think that (on) our court, some of the justices have engaged in results-oriented decision making, and I think the guy that I’m running against is the worst offender.”

Wheat said he takes the principle of a nonpartisan, independent judiciary seriously, and noted that VanDyke was the one injecting partisan politics into the campaign.

“I think litigants want to know their case is being shared by a judge who doesn’t have a partisan position on things,” he said.

Wheat’s campaign contributors are mostly attorneys, while VanDyke’s contributions have come from prominent GOP legislators and party luminaries, plus the socially conservative Family Research Council and Montana Family Foundation.

VanDyke also has received donations from many former Gibson Dunn colleagues, among them Ted Olson, solicitor general under former President George W. Bush, and Eugene Scalia, son of Supreme Court Justice Antonin Scalia.

But the outside independent expenditures have dwarfed the individual donations. The national Republican State Leadership Committee has spent tens of thousands of dollars buying TV ads supporting VanDyke’s campaign. It is part of the group’s Judicial Fairness Initiative to elect state-levels conservatives, and the RSLC calls VanDyke a “principled conservative.”

Two other independent-expenditure groups have joined the fray, the pro-VanDyke Montanans for Fair Justice and the pro-Wheat Montanans For Liberty and Justice.

University of Montana School of Law professor Anthony Johnstone said the risk of that kind of money entering nonpartisan judicial races is that it could cause the public to question the independence of the courts.

“But that’s a risk that Montanans have willingly taken in exchange for having direct control of the Supreme Court through elections,” he said.

None of that makes a difference in how he would judge if elected, VanDyke said.

“If you want some sort of conservative activist judge who’s going to twist the law to make it into a more conservative law, don’t elect me,” he said. “Don’t support me because that’s not what I’m going to do.”