It’s about time. A Michigan jury on Tuesday found Jennifer Crumbley guilty of four counts of involuntary manslaughter. Crumbley, whose son Ethan killed four and wounded seven in a 2021 shooting at Oxford High School, is being held accountable not for his actions, but her own.

It’s no crime to be lousy parents, though Crumbley and her husband James certainly test that proposition. Their son, under siege by lurid fantasies, sent text messages to his mother pleading for help. She didn’t reply. Ethan texted a friend about having asked his parents to get him desperately needed counseling. Instead, Ethan said, his father gave him some pills and told him to “suck it up.” Only 15 years old, engulfed by frightening hallucinations and homicidal ideation, the boy was left to his own devices. Well, not entirely.

The Crumbleys offered young Ethan a remedy familiar to anyone who follows the pathological storyline of America’s young, white, male mass shooters. What the Crumbleys’ deeply disturbed boy really needed, it seems, was a semi-automatic firearm and plenty of ammo.

The Crumbleys, who had previously left a pistol where Ethan had accessed it, purchased a 9-millimeter Sig Sauer semiautomatic for their tormented son. Jennifer Crumbley even took her son to a shooting range to get a taste of the firearm’s capabilities. Ethan subsequently used the gun to shoot up his school. He was sentenced in December to life without parole.

In an appeals court ruling last year, a Michigan judge wrote that it was reasonable to conclude that the Oxford massacre depended on the Crumbleys’ “decision to purchase their mentally disturbed son a handgun, their failure to properly secure the gun, and most importantly, their refusal to remove [Ethan] from school when he made overt threats to hurt other people.”

A veritable cortege of parents has trod the same grim path.

The mother of the killer who gunned down 20 children and six adults at Sandy Hook Elementary School in 2012 kept an arsenal within easy reach of her severely disturbed son. For recreation, she took him to the shooting range to familiarize himself with the tools that the 20-year-old would deploy in one of the most horrific mass murders in American history.

The mother of the gunman who killed nine people at an Oregon community college in 2015 told investigators that her son had been “born angry” and enjoyed watching videos of killings. Yet guns were added to this combustible cocktail. Indeed, she said, their home had so many firearms, maintained in such chaos, that after her son committed mass murder, she was unable to tell which, if any, guns were missing.

The dead and wounded have failed to dissuade the denizens of American gun culture that firearms don’t magically cure the problems that guns, in reality, create. Guns, in this make-believe world, are defensive instruments of peace and justice. Road rage without a gun is a nasty shout or an obscene gesture. With a gun, it’s a dead girl. Parents who make guns available to troubled offspring are at last receiving scrutiny. The father of the Highland Park, Ill., mass shooter who killed seven and wounded 31, pleaded guilty to misdemeanor reckless conduct for sponsoring his son’s gun ownership application. A Virginia mother whose 6-year-old brought the mother’s gun to school and shot a teacher was sentenced to two years in prison for felony child neglect.

The guilty verdicts against Jennifer Crumbley represent a leap forward. (Her husband is scheduled to go on trial in March.) Facts have proved impervious to gun culture. Perhaps accountability can begin to make some headway.

Francis Wilkinson is a Bloomberg Opinion columnist covering U.S. politics and policy.