A conservative activist is alleging that Supreme Court Justice Louis Butler has failed for years to report in-kind campaign contributions from a Milwaukee law firm.

But a lawyer for the firm said the allegations aren't true, and that the complainant is a "well-known right-wing crank" who is trying to generate negative publicity about Butler just days before the April 1 election.

The lawyer, Jeremy Levinson, also said all people at the firm who performed work for Butler over the years did so as volunteers, help that doesn't need to be reported under state campaign finance laws.

Levinson said the firm billed Butler's political consultant for any materials used by the firm to process political contributions to Butler. Butler has paid the firm $1,000 for political advice, he said.

"There's nothing here," Levinson said. "We've done it way above board."

Butler is being challenged by Burnett County Circuit Judge Michael Gableman. The race is nonpartisan, but, in general, liberals are supporting Butler and conservatives are supporting Gableman.

Robert Dohnal, of Wauwatosa, who publishes the Wisconsin Conservative Digest and has been involved in Republican politics for years, made the allegations against Butler in complaints he filed this week with the Government Accountability Board and the Wisconsin Judicial Commission.

In the complaint, Dohnal said Butler's campaign has used the Friebert, Finerty & St. John law firm for several years to receive and process campaign contributions but never reported the work or office supplies needed to do it as an in-kind campaign donation as required under law.

"What they're doing is illegal," Dohnal said. "They're subsidizing his campaign."

Officials from the judicial commission or the accountability board couldn't be reached for comment.

Darrin Schmitz, a spokesman for Gableman, said Butler's campaign should "come clean" about the work by the law firm's employees. A spokesman for Butler's campaign could not be reached.

State Journal reporter Dee J. Hall contributed to this story.