Few would quarrel with the proposition that a policeman ought to be able to shoot someone who is trying to kill him. Sometimes these judgment calls are easy: a man has just shot his wife and then turns his gun on the policeman who had been trying to calm the "domestic disturbance." Other cases are more complicated because, in retrospect, other options might have been tried. Earlier this week in New York, for instance, a policeman shot and killed a 67-year-old woman who was resisting eviction. She was 5-foot-8-inches, 300 pounds and had lunged with a knife at his partner. Perhaps two officers should have been able to subdue a severely disturbed woman of that age without using deadly force, but maybe they couldn't have. In life and death situations in which decisons must be made instantly, the benefit of the doubt goes to the policeman.

On Tuesday, the Supreme Court heard arguments in a police-shooting case from Memphis that did not involve a threat to the officers. At issue were rules governing the use of deadly force to stop a suspect fleeing from the scene of a crime. In common law, and in 24 states including Tennessee, police can shoot to stop a suspect when they have probable cause to believe he has committed a felony. In other jurisdictions, deadly force is authorized only when the suspect is dangerous or when there is probable cause to believe he has committed a violent felony. Edward Eugene Garner, an unarmed 15-year-old boy, was shot and killed 10 years ago by a Memphis police officer while he was running from an unoccupied house he had just burglarized. The offense was a felony, but not a violent one, and the boy's father, seeking damages, claims that the Tennessee statute granting broad powers to the police is unconstitutional.

The common law rule may or may not be held to be unconstitutional, but surely it is outdated and unwise. Many law-enforcement officials agree. A brief filed by the Police Foundation and a group of police chiefs and sheriffs makes the point that broad deadly force statutes increase tensions between the community and the police and, in the long run, make the job of law enforcement more difficult. A prudent, narrow rule that limits a violent response to a violent situation makes sense, even if some thieves occasionally, and temporarily, get away.