THE HEADLINE on the wire service story was a mind-boggler: "Educator Gets 60 Days in Wife Killing." Sixty days? Surely there must have been some mistake. Sixty days for accumulated parking violations, maybe, or for an especially rowdy, peace-disturbing party . . . but certainly not for "wife-killing." Wrong. The headline was not an editor's error but a true account of a Missouri court's idea of justice.

Ron J. Karraker, the defendant in this case, was chairman of the department of educational psychology at the University of Missouri-Kansas City in 1980 when he picked up a hammer one night and killed his wife. He then had the presence of mind to bundle the body into a car, drive to Lake Jocomo, east of the city, and dump the body into the lake. He was soon arrested and charged with second-degree murder. So far, so good. But Mr. Karraker pleaded not guilty on the grounds that his act had been the product of a mental disease or defect. This is the very broad rule for acquittal by reason of insanity that was abandoned in the District of Columbia 10 years ago. Missouri is one of the few states that still uses this standard.

According to Kansas City prosecutors, Mr. Karraker had no history of mental illness or violence, and no one claimed that he was mentally ill at the time he was brought to court. Nevertheless, five of the six psychiatrists and psychologists who examined him found that he was temporarily suffering from a mental disease at the very time he killed his wife. Fearing that he would be acquitted of second-degree murder on the testimony of these medical experts, the prosecutors chose to accept a plea of guilty of manslaughter instead of proceeding with the trial.

Given the broad nature of Missouri's insanity defense and the fact that manslaughter is punishable by 10 years in prison, it is difficult to question the judgment of the prosecutors at this point. What must have astounded them, however, was the judge's sentence. Judge Gene R. Martin of the Jackson County Circuit Court suspended the entire jail term except for 60 days and ordered that the defendant then spend the next 22 months teaching inmates of the local jail. One wonders what he will teach.

Judge Martin may believe that his resolution of this case was a practical approach to sentencing. Coming so soon after the controversy over the Hinckley verdict, it is sure to add to public confusion over the standards that are applicable in our criminal courts. Rules governing the insanity defense vary widely among the states, and in some instances it appears that even a threat to raise the defense is a valuable tool in plea bargaining. And judicial discretion in sentencing is broad, so broad that there is often great disparity among sentences handed down by different judges for identical crimes.

Most criminal law experts now support legislation that Congress has been considering for some years that would set mandatory minimum and maximum sentences, within a narrow range, for federal crimes. This Missouri case, where a defendant who pleads guilty to killing his wife with a hammer and hiding her body in a lake gets 60 days in jail, will surely be used as an example of the kind of judicial discretion that confuses the public and can eventually undermine that confidence in the judicial system that is necessary for the preservation of a just and stable society.