I just got off the phone with Professor William Cronon of the University of Wisconsin, a harsh critic of Scott Walker and other Wisconsin Republicans. He’s accusing the Wisconsin GOP of retaliating against his criticism with what he calls “McCarthyite” tactics.

This could be an important story, so bear with me. Earlier this week, Cronon published an Op ed piece in The New York Times that contained a scathing attack on Walker and the Wisconsin GOP, alleging that their anti-union proposal represents a radical break from Wisconsin history. Cronon also posted a blog entry that alleged that a little-known conservative outfit called the American Legislative Exchange Council, which tries to engineer right-wing policies in state legislatures, is behind the Wisconsin anti-union push.

Shortly thereafter, Cronon says, the University of Wisconsin’s attorneys received a request from the Wisconsin GOP, under the state open records law, for copies of a huge amount of Cronon’s emails sent from his state account at the university. That request is posted right here. Tellingly, the Wisconsin GOP asked for Cronon-authored emails that contain a range of union-related keywords, such as “AFSCME,” “collective bargaining,” “recall,” etc.

It’s a remarkable request, as TPM notes. The Wisconsin GOP is apparently using the state’s open records law to request the private emails of a university professor who criticized Walker and Republicans.

Why would the Wisconsin GOP want access to Cronon’s private emails?

Cronon theorizes, based on the keyword requests, that Wisconsin Republicans are trying to catch him in violation of state university rules by using a state email account to engage in “lobbying and electioneering to try to unseat these Repubican legislators.” In other words, he says, Wisconsin Republicans want to damage him professionally in response to his criticism of them.

“That’s what they’re hoping to find,” Cronon says. “They’re trying to intimidate me. What they’re saying is that if an academic raises these kinds of questions, we’re going to make his life really uncomfortable. Intimidating people from asking legitimate questions is a McCarthyite tactic.”

Cronon says the Wisconsin GOP will not find evidence of what they’re looking for. “It’s not there,” he says.

The Wisconsin GOP did not immediately respond to a request for comment. This is going to get very interesting — more when I learn it.

UPDATE: Post edited slightly for accuracy.