The knock on the door in the dead of night is the stuff of “Darkness at Noon,” and of the state of Wisconsin.

To the question of whether armed police can storm your house and take away your personal effects and tell you to shut up about it, based simply on your political advocacy, Wisconsin answered for years, “Why, yes, they can — now please, shut up about it.”

The so-called John Doe investigations into Gov. Scott Walker and conservative groups in Wisconsin have been an ongoing travesty that — now that Walker is entering the presidential stage — should be considered a national disgrace. Walker’s opponents weaponized campaign-finance law, literally.

Journalist David French has talked to families targeted in the John Doe raids for the first time, and their stories are harrowing. Shouting officers at the front door in pre-dawn raids, at least once with a battering ram. Armed police rifling through and carting off their belongings, down to and including a daughter’s computer. And warnings to stay silent.

The targets were told not to tell their lawyers, or their friends, or their neighbors. When armed cops storm the house next door, people often wonder why, but the targets were forbidden from discussing what happened. As French points out, this wasn’t the right to remain silent and avoid self-incrimination, but an order to remain silent and not to make any professions of innocence. They had a keener sense of due process in Salem, Mass.

The investigators were, among other things, fishing for campaign-finance violations, on dubious grounds. So, for exercising their First Amendment rights, some targets were denied their First Amendment rights. This is the Bill of Rights, via Kafka and Inspector Javert.

The investigations have been such a long-running farce that there is John Doe I and II. As Scott Walker’s first campaign for governor got underway in 2010, the Milwaukee district attorney, John Chisholm, opened the initial John Doe investigation under a proviso of the law that allows officials to keep their targets secret and to compel them to hush up.

A partisan Democrat whose wife was a shop steward for a teachers union, Chisholm investigated everything possible related to Walker for a couple of years, without really laying a glove on him. It was in the run-up to Walker’s re-election campaign that, with the help of a compliant judge, John Doe entered its next phase of harassment of conservative groups.

Investigators swept up personal emails, and issued wide-ranging subpoenas, including information on donors. The Wisconsin Club for Growth describes in court filings how its activities were hindered, as people began refusing meetings, donors got nervous, and one of its key officials, Eric O’Keefe, wasn’t allowed to explain the nature of the investigation. O’Keefe, who has been courageous in resisting the investigations, has said, “The process is the punishment.”

And the offense was backing the wrong side in a highly contentious political dispute. It’s one thing for kids with bongo drums to register their opposition to Scott Walker; it’s another for armed agents of the state, operating with the force of law, to be used as essentially a political cudgel.

The John Doe investigation has bogged down under the weight of its own ludicrous unfairness, and various court challenges. The Wisconsin Supreme Court could soon rule to halt the investigations altogether, and the United States Supreme Court is set to decide whether it will consider a federal lawsuit brought by Eric O’Keefe and the Wisconsin Club for Growth.

Wisconsin legislators are considering scaling back the law enabling John Doe investigations to prevent future abuses. The John Doe process might make sense for unraveling a dangerous criminal syndicate; it isn’t appropriate in a tenuous campaign-finance investigation, let alone as a tool of intimidation against people on the wrong side of a political argument.

The politicized knock on the door in the night isn’t right for Wisconsin, or anywhere else in the United States of America.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.