WHEN THERE IS a wild tiger in the streets, you don't ask whether he actually means to harm you or whether his fantasies have produced an irresistible impulse to kill. You just want him off the streets. And even where a defendant may not be dangerous, justice requires that the society's values be upheld and reinforced. These include both compassion for the helplessly deranged and an insistence that those who are not deranged be held responsible for their acts. Did the Hinckley jury reach the right decision as between these two values? Along with many others, we were astonished and disturbed by what it did. That, however, says less to us about the character and competence of the jury than it does about the unsatisfying place to which the criminal justice system has come.

First, in defense of the jury: it was instructed to find Mr. Hinckley not guilty by reason of insanity unless it believed the government had failed to prove beyond a reasonable doubt a negative--that he was not mentally incompetent at the time of the shooting; this is in itself an interesting aspect of the law. And although it was easy to reach one verdict from reading second-hand accounts of the proceedings, it is important to remember that the jury over eight weeks of trial heard and saw and knew things none of us did. Surely one must give these 12 people the benefit of the doubt, a presumption that what they did, in terms of what they heard in testimony and what they were told their duty consisted of, was not the work of 12 crazy citzens.

There is something to be said for the law too. The fact is that acquittals on grounds of insanity are extremely rare. American courts have wrestled with the legal and moral implications of the insanity defense for 150 years; and although in the District of Columbia three different standards have been used in the last 30 years, such acquittals have always been the exception to the rule. Nor, we suspect, as disturbed as most people are by the disposition of the Hinckley case, would they want whatever new standard emerges from the reexamination that is sure to occur now to eliminate altogether those elements of extenuation and comprehension of the nature of criminality that have evolved over the years.

But when you have said all that, you still have not dealt with what was troubling in the Hinckley trial and verdict. It seemed to evoke every absurdity and easy practice and illogical and/or dangerous trend in the criminal justice system. We suspect that people are not so much disturbed by the likelihood that John Hinckley will shoot someone else or that he will not himself suffer a penalty as by the feeling, cumulative and finally overpowering, that trends in legal standards and in our psychiatrically oriented culture have led toward a place where we are disarmed--unable or simply not permitted either to honor our values or to protect the innocent and unsuspecting from acts of violence.

There is argument that the current standard be abandoned and a new verdict of "guilty but insane" be put in its place. That still leaves the judgment to the jury, which is asked to weigh medical testimony and, on the basis of it, to make a juridical finding. And to argue that the entire question of sanity be left until after a finding of guilty--presumably to some psychiatric group or other--does take from the jury system its traditional role of making a finding as to intent, motive, responsibility.

Something new has to be considered. The Hinckley case is not every case, but it strikes us, and we suspect it strikes a great many other citizens, as essentially representative in the challenges it poses to the institutions the society has constructed to save it from that tiger in the streets. In this instance, the tiger is the specter--for too many Americans, the reality--of unchecked violence. This case cannot be made to bear the burden of all the accumulated faults, real and imagined, of the criminal justice system. But it can become the vehicle by which the society assures itself that its values are being more safely and satisfactorily affirmed than they are today.