Wisconsin Gov. Scott Walker has had a massive left-wing target on his back ever since he ran for Governor in 2010, but particularly after 2011 when Walker signed into law a bill scaling back some public sector union collective bargaining rights.

There are few, if any, Republican politicians as hated on the left as Walker.

Walker’s not the most ideological Republican, but he is singled out because he so soundly and repeatedly defeated national efforts to stop collective bargaining reform.

The demonization of Walker is pervasive, and so-called “John Doe” investigations always have been an integral part of that effort. The mere pendency of such investigations is a critical part of anti-Walker messaging.

“John Doe” investigations in Wisconsin have been around for over a century, but only recently have they been used as political tools. Everything surrounding these types of investigations is secretive. They are commenced with a secret request to a judge, and a judge has to approve subpoenas.

Neither the persons who are the focus of the investigation nor persons subpoenaed are permitted to disclose to others any information about the existence or conduct of the investigation.

In 2010, local Democratic prosecutors began “John Doe No. 1,” an investigation of Walker’s time as Milwaukee County Executive, alleging that Walker supposedly misused the office for political purposes. The pendency of a John Doe investigation was used against Walker.

In 2011, the Wisconsin state legislature passed, and Walker signed, a law scaling back some public sector union collective bargaining. In the recall campaign launched against Walker, John Doe No. 1 again was used against Walker to create insinuations of corruption. It didn’t work, and Walker survived the recall.

After two years of effort, John Doe No. 1 was closed in 2012 with no evidence of abuse by Walker, but that doesn’t stop Walker opponents from claiming he was tainted by the probe.

Local prosecutors however started a second John Doe proceeding in February 2012, although its existence was not publicly acknowledged until 2013.

In secret filings in John Doe No. 2, at the time known and seen only by prosecutors and the judiciary, prosecutors alleged that Walker headed a “criminal scheme” to violate campaign finance laws.

Two judges have looked at John Doe No. 2, and both have said there is no case against Walker or his supposed co-conspirators.

In the state court action, a Judge refused to issue subpoenas, finding the prosecutors “do not show probable cause that the moving parties committed any violations of the campaign finance laws.”

A second time, this time in federal court, a judge looked at the allegations, and found that even if everything the prosecution claimed was true, no crime was committed and that the prosecutors violated the targets’ First Amendment rights.

So twice judges have found that there is no case against Walker or the others targeted.

Yet last week, pursuant to an appeals court order, some records were unsealed, in which the discredited allegation of a “criminal scheme” was released to the public.

Since then, the media has run wild with the allegation, while downplaying or completely ignoring the judicial findings. Headlines in the mainstream media scream the words “Criminal Scheme,” as left-wing activist websites treat the claims as if they were proven.

But none of this is proven. It’s just a smear by local prosecutors out to get Walker and aided and abetted by lazy and/or dishonest media.

In federal court on Thursday, June 19, 2014, in refusing to release more records the judge summed up what is happening: Prosecutors were seeking “refuge in the Court of Public Opinion, having lost in this Court of law.”

The John Doe proceedings always have been politically motivated, and used in the war against Scott Walker.

It is no surprise that as Walker is being talked about as a potential presidential candidate, the smear has resurfaced and is being aided and abetted by the media.

After years of local prosecutors and left-wing activists working off the same playbook, perhaps these tactics will backfire in favor of Governor Walker.

William A. Jacobson is a Clinical Professor of Law at Cornell Law School, and publisher of the Legal Insurrection blog.