Updated Nov. 15, 2013 6:53 p.m. ET

Americans learned in the IRS political targeting scandal that government enforcement power can be used to stifle political speech. Something similar may be unfolding in Wisconsin, where a special prosecutor is targeting conservative groups that participated in the battle over Governor Scott Walker's union reforms.

In recent weeks, special prosecutor Francis Schmitz has hit dozens of conservative groups with subpoenas demanding documents related to the 2011 and 2012 campaigns to recall Governor Walker and state legislative leaders.

Copies of two subpoenas we've seen demand "all memoranda, email . . . correspondence, and communications" both internally and between the subpoena target and some 29 conservative groups, including Wisconsin and national nonprofits, political vendors and party committees. The groups include the League of American Voters, Wisconsin Family Action, Wisconsin Manufacturers & Commerce, Americans for Prosperity—Wisconsin, American Crossroads, the Republican Governors Association, Friends of Scott Walker and the Republican Party of Wisconsin.
One subpoena also demands "all records of income received, including fundraising information and the identity of persons contributing to the corporation." In other words, tell us who your donors are.

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The probe began in the office of Milwaukee County Assistant District Attorney Bruce Landgraf, though no one will publicly claim credit for appointing Mr. Schmitz, the special prosecutor. The investigation is taking place under Wisconsin's John Doe law, which bars a subpoena's targets from disclosing its contents to anyone but his attorneys. John Doe probes work much like a grand jury, allowing prosecutors to issue subpoenas and conduct searches, while the gag orders leave the targets facing the resources of the state with no way to publicly defend themselves.
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The subpoenas don't spell out a specific allegation, but the demands suggest the government may be pursuing a theory of illegal campaign coordination by independent groups during the recall elections. If prosecutors are pursuing a theory that independent conservative groups coordinated with candidate campaigns during the recall, their goal may be to transform the independent expenditures into candidate committees after the fact, requiring revision of campaign-finance disclosures and possible criminal charges.
Perhaps the probe will turn up some nefarious activity that warrants this subpoena monsoon and home raids. But in the meantime the effect is to limit political speech by intimidating these groups from participating in the 2014 campaign. Stifling allies of Mr. Walker would be an enormous in-kind contribution to Democrats. Even if no charges are filed, the subpoenas will have served as a form of speech suppression.

Mr. O'Keefe told us that the flurry of subpoenas "froze my communications and frightened many allies and vendors of the pro-taxpayer political movement in Wisconsin and across the country." Even if no one is ever convicted of a crime, he says, "the process is the punishment."

Wisconsin Democrats, jack-booted thugs in this case, are using the special prosecuter's office to do more intimidation of conservative groups. Justice is a formula now, no longer belonging to God, but exclusively to those in power.

This is so wrong. A stench is settling over American governmental agencies. Honor, loyalty and obeisance are to be paid to the powers that be. This isn't government of by and for the people anymore. This is party politics controlling justice and administering it according to their preferences.

How did this all come about so quickly?