Former University of Cincinnati police officer Ray Tensing appears for his arraignment in the shooting death of motorist Samuel DuBose. (John Minchillo/Associated Press )

AS THE nation approaches the first anniversary of the unrest in Ferguson, Mo., its effects are more visible than ever — in North Charleston, S.C., Baltimore, Waller County, Tex., and now Cincinnati. Had the nation not fixed its eyes on police behavior over the past year, it’s impossible to know how law enforcement officials in Cincinnati’s Hamilton County would have reacted to the shooting of Samuel Dubose at the hands of Officer Raymond Tensing. But it’s possible the situation in Cincinnati would be very different.

Mr. Tensing fatally shot Mr. Dubose during a traffic stop on July 19. Ten days later, county prosecutors secured a murder indictment against the officer, who was subsequently fired from the University of Cincinnati Police Department. They also released official police body camera footage, which appears to show that Mr. Tensing fell to the ground but was not “dragged” along by Mr. Dubose’s car, as the ex-officer had claimed. “The officer was wrong, and when we’re wrong, we have to be held accountable,” Cincinnati Police Chief Jeffrey Blackwell said Wednesday, even as he warned that the city would not tolerate violence on the streets.

By moving quickly, making clear statements and respecting the community’s interest in transparency, these officials reduced the likelihood of a violent reaction. “I thought it was going to be covered up,” Audrey Dubose, Mr. Dubose’s mother, said at a news conference at which the family called for protests to be “peaceful and non-aggressive.” Just as no one wants to see law enforcement officials fumbling as they did in Ferguson, no one wants to see the wanton violence that raged on the streets of that town.

What’s beyond doubt is that the Ferguson imbroglio led directly to important policy changes. The debate about the value of police body cameras, footage from which proved to be crucial in the Dubose case, is essentially over. Policymakers are also reexamining police equipment, training and tactics, and there’s a long-overdue push to gather better data about police use of force.

It’s true that for those pushing reform, the incident that led to last year’s Ferguson episode turned out not to be an ideal example of police misbehavior. A thorough Justice Department investigation showed that there wasn’t much of a case that the shooting of Michael Brown by Officer Darren Wilson was an instance of unreasonable force. There’s a lesson in that, too: Even as things change, allegiance to facts and timeless legal protections for defendants must remain at the core of the nation’s criminal justice system. The process must play out fairly for Mr. Tensing.

Yet for too long that system has felt stacked to too many people, its noble principles unevenly applied, particularly in minority communities. Ferguson brought years of legitimate grievances to the front of the public’s mind. The nation’s struggle to come to grips with its racist past, the persistence of bias and, regardless of who’s hurt, the much-too-widespread reality of unprofessional policing is far from finished. But Americans are more focused on these issues now than they have been in many years — and that’s having positive, real-world effects.