By a recent dereliction of duty, the Supreme Court has demonstrated that sometimes the proper regret about judicial activism is that there is too little of it. The court refused to hear a case that would have allowed it to clarify a doctrine that has become an impediment to remedies for even gross government violations of individuals’ constitutionally guaranteed rights.

In 2016, Kodi Gaines, then 5, was seriously wounded by a Baltimore County police corporal who was, he later explained, “hot” and “frustrated” during a six-hour standoff on a sweltering August day in a Baltimore suburb. The corporal was, however, protected by court-granted “qualified immunity” from liability for his appalling misjudgment. Qualified immunity is frequently misapplied because the Supreme Court has declined to dispel confusion that has proliferated in the absence of clarity that the court could have provided by taking up Kodi’s case.

According to court documents, when two police officers arrived to serve Kodi’s mother with misdemeanor arrest warrants (arising from traffic violations), they encountered her with Kodi, a shotgun in her lap. The officers withdrew and summoned more than 30 backup officers. They surrounded the apartment building and cut its power, and hence its air conditioning. When Kodi’s mother went to the kitchen to make him a sandwich, she took her shotgun but pointed it at no officer. Although she seemingly posed no threat of flight or imminent harm, the police corporal, who had been in an adjacent apartment, and who testified that he knew Kodi was somewhere behind the kitchen’s drywall partition, fired his rifle at the mother. The bullet hit her in the back, ricocheted off the refrigerator and struck Kodi’s face. The corporal then entered the apartment and killed the mother with three more shots, one of which shattered Kodi’s elbow. His injuries required multiple surgeries.

In a suit filed on Kodi’s behalf, a jury awarded him monetary compensation for violations of his constitutional rights. But an appellate court found that no “well-settled law” established that an innocent bystander has a right to be free from injury from a gunshot intended for someone else. So, the “hot” and “frustrated” corporal was protected by qualified immunity.

In 1871, Congress legislated that government officials who violate citizens’ constitutional rights “shall be liable to the party injured.” In 1982, however, the Supreme Court substantially weakened this guarantee. It held that for an official to receive qualified immunity for his conduct, the conduct must violate “clearly established law.” This, in turn, has been construed to mean that trivial differences between the fact patterns in even egregious violations of rights mean that the abusive official did not have “fair warning” that his abuses, however glaring, were wrong.

The Supreme Court has, however, held that such immunity does not shield officers whose constitutional violations are “so obvious” and “clear” that a reasonable officer’s sense of justice should suffice as “fair warning” of their acts’ illegality, even absent a precisely similar precedent.

So, the Maryland court erred in considering only whether relevant prior cases exist. It wrongly ignored — as various federal circuit courts of appeal have done — the Supreme Court’s obviousness principle: Some violations are so shocking that, when denying qualified immunity, it is unnecessary to find a prior case with closely similar fact patterns.

The obviousness principle rescues the law from this perverse outcome: The most luridly flagrant violations of rights are apt to be sui generis, so government agents who commit them would be especially likely to be shielded by qualified immunity because there are no precisely similar precedents for denying it.

Qualified immunity was originally intended to protect endangered police making split-second decisions in, for example, high-speed chases or shootouts with armed suspects. But courts have granted qualified immunity to officers who stole more than $225,000 in cash and rare coins while executing a search warrant. To a deputy sheriff who, while trying to shoot an unthreatening pet dog, wounded a 10-year-old child. To state investigators who, without a warrant, entered a doctor’s office and searched the medical records of patients. Even to some university bureaucrats because their flagrant denial of some students’ First Amendment rights did not violate “clearly established law.”

Qualified immunity properly shields from personal liability the overwhelming majority of competent police officers who might make honest misjudgments in high-pressure situations. But as a federal appellate judge has said, qualified immunity has begun to look like unqualified impunity for misbehaving public officials. The Supreme Court should have corrected this with some dutiful activism, using Kodi’s case to end confusion among lesser courts.

George Will writes a column for the Washington Post.