- - Wednesday, May 7, 2014

Campaign finance laws have become the liberal weapon of choice to silence conservatives. This is lately demonstrated in Wisconsin, where a Milwaukee County district attorney has spent the past four years using an obscure “John Doe” investigation to harass prominent Republicans. A federal judge put an end to the vendetta Tuesday.

Eric O'Keefe, who heads the Wisconsin Club for Growth, became the primary target of the investigation. He got a subpoena ordering him to surrender every scrap of paper generated by his office between March 2009 and now. He was told he would be jailed if he told anyone, even his wife, about the court order.

Similar demands were delivered to 29 groups that dared support Gov. Scott Walker in his 2010 election campaign. Each faced the all-but-impossible burden of producing volumes upon volumes of documents, and dealing with lawyers and deadlines distracted them from their other work. Donors feared, with good reason, that they would be dragged into the courtroom battle. Some kept their checkbooks shut tight. Club for Growth says it lost $2 million in expected donations.

District Attorney John Chisholm justified this witch hunt with the claim that the conservative groups’ advocacy was political activity, subject to Wisconsin law and was not an exercise of protected First Amendment speech. This week, good sense and justice prevailed at last. “This interpretation is simply wrong,” said U.S. District Judge Rudolph T. Randa. From his courtroom in Milwaukee, Judge Randa ordered the district attorney to halt the investigation, return all seized property and “permanently destroy all copies of information and other materials obtained through the investigation.”

Judge Randa cited McCutcheon v. Federal Election Commission, in which the Supreme Court ruled last month that a valid campaign finance law must target actual corruption, not political speech. The only statutes that meet this standard are those that prevent candidates from trading “dollars for political favors.”

Club for Growth raises money to advocate for low taxes, reduced government spending, a free-market health care system and school choice. The club promotes policy solutions, and does not ingratiate itself with the tax-and-spend political establishment.

Pious liberals, however, insist that all money in politics is evil — unless the money comes from the public treasury or union dues. President Obama set the tone in 2010 when he set aside decorum and used his State of the Union address as an opportunity to rebuke Supreme Court justices in the audience for their campaign finance decisions.

The transparently partisan Democratic scheme is finished in Wisconsin. Mr. O'Keefe is naturally relieved. “I look forward to re-engaging in Wisconsin and speaking out on issues I believe in,” he says. That’s good news, because Wisconsin needs more voices speaking out loudly about the virtues of limited government. There’s no greater proof of this need for shrinking the state’s power than that a partisan district attorney could get away with abusing the legal system for so long.

Mr. Obama and his allies are eager to use the power of government to purge “bad” money from the political system. This is a dangerous impulse, as Democrats want to be the judge of what’s good and what’s bad. “As other histories tell us,” Judge Randa observed, “attempts to purify the public square lead to places like the guillotine and the gulag.”