Billionaire campaign donor David Koch has rarely spoken in public about the central role he has played in the election of Scott Walker as governor of Wisconsin, the defense of Walker’s embattled governorship and, now, Walker’s desperate attempt to defeat the recall election that more than one million Wisconsinites have demanded.

Until now. And that has raised fundamental legal and political questions about the manipulation of Wisconsin politics by out-of-state billionaires.

It is no secret that Koch and his billionaire brother, Charles, have long been a Walker supporters. Their Koch Industries PAC was the second-highest donor to Walker’s 2010 campaign, donating $43,000. The PAC also gave $1 million to the Republican Governors Association, which streamed spending into Wisconsin on behalf of Walker’s election.

And the Americans for Prosperity groups the Kochs founded and financed certainly seemed to be active on Walker’s behalf.

But AFP and its foundation could not campaign openly for Walker or other candidates, as they are tax exempt organizations operating under laws that protect civic and educational charities.

So it was incredible when David Koch admitted in an interview with the Palm Beach Post that he planned to support Walker with spending by AFP. “We’re helping him, as we should,” Koch said of Walker. “We’ve gotten pretty good at this over the years. We’ve spent a lot of money in Wisconsin. We’re going to spend more.”

The Post added: “By ‘we’ he says he means Americans for Prosperity, which is spending about $700,000 on an ‘It’s working’ television ad buy in the state.”

Could Koch really be admitting to a violation for the Internal Revenue Service code that says organizations such as AFP are “absolutely prohibited from directly or indirectly participating in, or intervening in, any political campaign on behalf of (or in opposition to) any candidate for elective public office”?

It certainly sounded like it. And, on the Koch Industries website, a statement by Koch several days later said that: “as the Palm Beach Post story indicated, my comments concerning support for Governor Walker related solely to Americans for Prosperity and its activities in Wisconsin.”

Complaints have been filed with the IRS and the Wisconsin Government Accountability Board alleging—in the words of the Democratic Party of Wisconsin—“illegal use of tax exempt status by billionaire David Koch.”

There is no question that, based on what Koch has said, the complaints are legitimate. They come in the context of what will be an intense recall election. They should be investigated and addressed with an urgency that respects the timeline of that recall and the significance of threat posed to Wisconsin democracy.

John Nichols’s new book on protests and politics, Uprising: How Wisconsin Renewed the Politics of Protest, from Madison to Wall Street, has just been publshed by Nation Books. Follow John Nichols on Twitter @NicholsUprising.