The Charlottesville Police Department reminded everyone on Monday why we have a justice system that requires accusers to make criminal cases beyond a reasonable doubt. And in doing so, the Charlottesville PD not only indicted one reporter's folly in publishing unproven allegations, but also skewered America's moral panic about college campuses, and the evasion of due process for the sake of political expediency.

The embarrassment of Rolling Stone's epic journalistic failure re-emerged on Monday in Charlottesville, home of the University of Virginia. Last year, the magazine published a 9,000-word indictment against UVA, saying the college had a "culture of hidden sexual violence" that protected rapists while leaving victims helpless. The article, written by Sabrina Rubin Erdely, told the story of "Jackie," a student who claimed to have endured a brutal gang rape at the Phi Kappa Psi fraternity during a party, only to have her friends discourage her from reporting it so that they could maintain their own social contacts, and UVA ignore the crime to avoid damage to the school's reputation.

The furious national outrage over the story prompted UVA to suspend the fraternity and cancel all Greek activity on campus, while giving fuel to activists who claimed that an epidemic of rape was sweeping American college campuses.

Stung by getting scooped in their own backyard, The Washington Post assigned T. Rees Shapiro to investigate the story, and found that no one else could corroborate anything about Jackie's claims. Erdely had not tried to speak with those accused about the supposed gang rape, and had gone along with Jackie when she insisted that Erdely not contact her friends, either. Shapiro and other reporters did the due diligence that Rolling Stone eschewed, and discovered that Jackie's friends had different recollections about the night in question, and Jackie's physical and emotional state as well. The story quickly unraveled, turning into a debate over journalistic ethics rather than sexual assault and campus discipline.

The Charlottesville Police Department, however, still took the original allegations seriously. They opened an investigation that took months. In the end, though, the investigation came up short of a definitive answer on Jackie's claims, in significant part because she didn't cooperate with the probe.

"We're not able to conclude to any substantive degree that an incident occurred at the Phi Kappa Psi fraternity house," Police Chief Timothy Longo told a press conference on Monday, "or any other fraternity house, for that matter." The cops did determine that Phi Kappa Psi never had a party on the night of the alleged attack, and that no one could be found that fit the description of the lead attacker. The man with whom Jackie had claimed to have a date that night turned out to be a high-school classmate who hadn't seen Jackie in years, a point discovered by the Post's Shapiro in December.

And yet, as Longo noted, their investigation couldn't definitively prove that nothing traumatic had happened to Jackie on that night in September 2012. They could demonstrate that Jackie had given false information in her story, but that was all.

That's the real lesson from the Charlottesville investigation. It's impossible to prove a negative — and that's why we have the protections afforded us through due process when it comes to allegations of criminality.

Activists, abetted by the Obama administration's pressure on schools to increase disciplinary actions for sexual harassment and assault, have pushed schools into using incredibly low standards of evidence in administrative hearings, while denying the accused opportunities to confront accusers, examine witnesses and evidence, or even put on an effective defense. In too many cases, those accused on college campuses find themselves in the impossible position of proving negatives. Instead of having normal due process, they find themselves in kangaroo courts, with their lives ruined on the basis of mere allegation.

Yes, Erdely's Rolling Stone article is a "crock," as Washington Post media critic Erik Wemple puts it. But so are attempts to have schools conduct witch hunts against people about whom nothing has been proven. We need to end presumptions of guilt and denial of due process now, and leave criminal investigations in the hands of professionals — like the Charlottesville Police Department — and not activists in pursuit of their own political goals.