Is Milwaukee County DA interested in pursuing criminal libel prosecutions of his political critics?

The Milwaukee Journal Sentinel (Patrick Marley) reports,

Prosecutors have largely been mum publicly about their probe of [Gov. Scott] Walker's campaign, and Walker recently has largely refrained from discussing the matter.

That changed Saturday after Walker on Friday spoke to WHO-AM in Des Moines about a recent report in the National Review detailing a 2011 police raid on the home of Walker aide Cindy Archer and ones in 2013 on those working for groups supporting him.

"I said even if you're a liberal Democrat, you should look at (the raids) and be frightened to think that if the government can do that against people of one political persuasion, they can do it against anybody, and more often than not we need protection against the government itself," Walker told the radio station.

"As (the National Review) pointed out, there were real questions about the constitutionality of much of what they did, but it was really about people trying to intimidate people…" Walker said.

"They were looking for just about anything. As I pointed out at the time, it was largely a political witch hunt."

The raids were conducted as part of a pair of investigations led by [Milwaukee County District Attorney John] Chisholm, a Democrat. On the second investigation, Chisholm was assisted by district attorneys from both parties and special prosecutor Francis Schmitz, a self-described Republican.

"As to defamatory remarks, I strongly suspect the Iowa criminal code, like Wisconsin's, has provisions for intentionally making false statements intended to harm the reputation of others," Chisholm said in a statement Saturday responding to Walker's comments.

DA Chisholm's suspicions appear unfounded: The Iowa criminal libel statute was repealed in the late 1970s, and Iowa law doesn't recognize common-law crimes. But Wisconsin does have a criminal libel law, which is used several times a year, as Prof. David Pritchard's excellent article on the subject demonstrates.

That law is not generally used for alleged libels related to political matters, but is that about to change? Is DA Chisholm is trying to signal that he may begin using Wisconsin's own criminal libel law against political figures—or commentators or journalists—who he claims are lying about him (or other political figures)? Is he just venting, and not intending for his speech to have any chilling effect? Is he simply speaking about Iowa law, with no intention of suggesting that he might use Wisconsin law to prosecute people in such situations? If you were a Wisconsin critic of DA Chisholm or his allies, whether you are in Gov. Walker's camp or not, how would you perceive this sort of statement?

I think there are credible arguments for the use of carefully crafted criminal libel law in some situations that involve purely private matters, though there are also credible arguments against it. But the use of criminal libel law in political disputes strikes me as much more troubling: much more likely both to stifle political debate (including true statements and expressions of opinion), and much more likely to be influence by the defendants' (and the prosecutor's) political positions.

UPDATE: Here's DA Chisholm's full statement.