In 1843, Daniel McNaughtan attempted to assassinate British Prime Minister Robert Peel. Instead, he shot the prime minister's private secretary, who languished for several weeks and then died. The shooting, according to The Times of London, was "carried out with the most cold-blooded determination" and in full view of numerous witnesses.

McNaughtan was tried for murder. He submitted a plea of insanity. The greatest barristers in England participated in the case, and well-known alienists -- specialists in insanity -- were called by each side. The jury rendered a verdict of not guilty by reason of insanity.

The public was outraged. Queen Victoria protested that "everybody is morally convinced" that McNaughtan killed the private secretary and was "perfectly conscious and aware" of what he did. Demands were made to change the law of insanity, and the issue was debated in the House of Lords, which did change the law. The resulting test -- called the McNaughtan Rules -- have served as the basis for insanity defense throughout the Anglo-American legal world for the past 140 years.

Now history has repeated itself -- as it so often does. The characters are different, but the public outcry is similar, and elected officials are busy competing with each other for who can flex the biggest muscles in the current attack on the insanity defense.

What can we learn from the Hinckley case against this historical background? The most important lesson is that the American jury is alive and well performing its assigned function. We have seen 12 ordinary citizens render an unpopular decision in favor of an unsympathetic defendant who had nearly killed a popular president. In finding Hinckley not guilty by reason of insanity, the jurors defied the government, rejected the conclusions of several learned psychiatrists and ignored public opinion. They apparently surprised the trial judge who seemed to have anticipated a guilty verdict.

Following the jury's verdict, a Senate sub committee convened hearings at which several of the jurors gave voluntary testimony about what happened in the jury room. Although the hearings were conducted with delicacy and sensitivity, the precedent established by legislative questioning of jurors is rife with dangers to the independence of the jury system. A juror should not have to worry about how he or she will answer hard questions concerning a controversial verdict.

It is noteworthy that the precedent has been established in a case where the jurors voted in favor of the defendant. I doubt whether the senators would have questioned jurors about a guilty verdict. If they had, they would have uncovered similar disturbing information about the jury process in cases of conviction.

The harings suggested that some of the jurors may have been confused by the psychiatric and legal jargon. This should come as no surprise. Jurors who vote for conviction in complicated fraud, conspiracy or tax cases are often confused as well by the accountants, actuaries and tax experts who testify for both sides -- as well as by the incomprehensible instructions they are often given by the trial judge.

In the end, the jurors must resort to their common sense and basic morality in cutting through the garble of obfuscation that is thrown at them. Sometimes they do a good job; sometimes they do not. That is the price we pay for the independence of the jury.

The hearings also suggest that some jurors may have felt pressure toward unanimity from other jurors. That too is a frequent phenomenon in cases where the jury ultimately renders a verdict of guilty. Indeed, there is a standard instruction that urges hold-out jurors to consider the views of the majority. The usual result of this "dynamite" instruction -- which is despised by the defense bar -- is to break a jury deadlock in favor of conviction. The jurors in this case displayed an admirable degree of independence in the face of enormous external pressures. And that is what the jury system is all about.

To their credit, most legislators have been careful not to criticize the individual jurors or the jury system. The "blame" for the Hinckley verdict has been placed on the law of insanity, and a vigilante atmosphere prevails among elected officials to change -- or even abolish -- the insanity defense. This is not surprising, since outcries for legal change often follow traumatic national events. Political shootings are invariably followed by calls for gun control, which are quickly muffled by the reality of the gun lobby. But there is no insanity defense lobby, and it is likely that Congress -- as well as state legislatures -- will succeed in revising the insanity defense. Changes will be made in the wording of the test, the burden of proof and the permissible range of psychiatric testimony. Perhaps we will end up with "guilty, but insane" instead of "not guilty, by reason of insanity." It is even possible, though unlikely, that the insanity defense will be abolished.

None of these changes will have the slightest impact on the safety of the community. This is so far a very simple, if sometimes forgotten, reality: namely, hardly anyone raises the insanity defense, and the few who do are rarely successful. If the insanity defense is problematic -- and, in several respects, it is -- it constitutes (in the words of my colleague, Alan Stone) "a pimple on the nose of justice." Far fewer than 1 percent of all criminal cases result in an insantiy acquittal, and in many of those cases the "victorious" defendant spends as much time behind the bars of a mental hospital as he would have spent behind the bars of a prison had he lost.

Although the insanity defense has little practical significance, its abolition would raise serious moral issues. The criminal law, as it has evolved from its most primitive origins, does not punish bad acts alone; it punishes such acts when they are committed by responsible beings acting with a particular state of mind. How many times have we heard the following bit of folk wisdom: "President Reagan and Press Secretary Brady weren't hurt any less because Hinckley may have been crazy"?

That is, of course, true. But it would be equally true if the president had been shot by a five-year-old child playing with a gun, mauled by a wild animal, or crushed by a falling rock. In the old days, the family of the victim would "punish" the object that had caused the hurt: the child would be whipped, perhaps even executed; the animal would be ritually destroyed; the rock would be shattered.

We have progressed over the past millenium so that now we distinguish between responsible beings who deserve punishment and nonresponsible causes of harm that must be controlled, but not punished. The insanity defense, by differentiating the many sane defendants from the very few insane ones, underlines the moral basis of the criminal law. It sends a message to the vast majority of criminals that they are to be held responsible for their criminal acts, because their harmful acts are different from those done by children, by inanimate objects and by the very few insane adults.

The insanity rules that emerged from the debates following the McNaughtan case back in 1843 strengthened the moral basis of the criminal law focusing on the defendant's ability to "know the difference between right and wrong" and to "know the nature and quality of the act he was doing." This test, like all complex oral distinctions, has not been without its difficulties. If the Hinckley verdict is seen as an occasion for intelligent discussion and reaffirmation of the moral basis of our criminal law, rather than as an excuse to rail against the abuses of a rarely invoked "loophole" defense, we will have learned an important historical lesson. Perhaps that is too much to expect from an opportunistic Congress responding to the demands of an angry and confused public.