"IN THE END," John W. Hinckley wrote, "I have become what I wanted to be all along, a psychotic poet." It took this country's legal system over a year and a half to take Hinckley at his word, and decide that his psychosis was more than just the imagined mask of a calculating evader of justice. Over a fifteen month period-- from the shooting spree of March 1981 to the June verdict of the following year--Hinckley was to emerge as the enigmatic author and protagonist of what he himself called "my melodrama."

For many Americans, though, the complicated medical, psychiatric and legal maneuverings of the trial and Hinckley's subsequent acquittal by reason of insanity seemed neither poetic nor just. The computer printout that served as a mere index to the papers filed in the case stretched to some fifteen feet. The medical and psychiatric interviews of Hinckley climbed into the hundreds of hours. The cost of the month and a half long trial totalled some two and a half to three million dollars, with federal charges at least three times that spent by the oil-rich Hinckleys.

It was the stuff of a different kind of poetry: public outcry, sensational cover stories and often misinformed media assertions about the ill health of the U.S. judicial system. Once again, it appeared--a view fuelled by the 30 to 40 reporters covering the trial--that justice had sold itself off to the highest bidder, and a nut at that.

Lincoln Caplan, a lawyer by training and frequent contributor to the New Yorker, manages in his book, The Insanity Defense and the Trial of John W. Hinckley Jr., to do what his friends in the press had little time to do. He has sifted the evidence, researched the precedents, and projected the Hinckley case outside itself and into a more general and philosophical consideration of the issues. All the while, he subtly weaves his argument and day by day New Yorker-style descriptions ("Jo Ann Moore Hinckley ... wore a salmon-pink outfit, with Peter Pan collar and bow, and spoke in a soft Texas accent") around the goings-on of an insanity trial being held at the same moment in the same city. The issues there are the same, but the costs less outrageous, the participants less famous and, instead of the prestigious firm of Williams and Connolly for the defense, it is the Public Defender Service.

Hinckley's are not the only delusions put on trial in Caplan's book; with him go much of the present Administration's legal thinking and some of that widespread and misinformed public opinion. Caplan's treatment of the insanity defense aims at discouraging us from seeing the defense as one or all of the following: an overused and therefore dangerous "legal loophole" (the words are, ironically, Richard M. Nixon's): a play-trial toy of the rich (the usual tabloid lore), or, thirdly, a legal contradiction (the view of behaviorists, who see free will as an illusion and absolve guilt for behavior caused by external forces. Such thinkers feel the judiciary must either bring the perpetrators of anti-social behavior into line by way of drugs, psychosurgery and therapy or, failing this, confine them).

CAPLAN'S own case is simply and convincingly put. In 1978, the last year for which data on the insanity defense were available, 40 million Americans were affected by some type of crime. Three fifths of the 10 million suspects were charged. And of these, only 1500 successfully pleaded insanity. And while psychiatry offers no insurance against violence, statistics on recidivism indicate that the probability of repeated crime by a treated mentally ill offender is somewhat lower than for a felon released from prison.

The insanity defense should not be viewed as a technical sieve that lets nervous assassins pass by judicial strictures with impunity. Not only is the defense used infrequently; when it is used, it is even less successful. Caplan's evidence is telling. After the 1983 passage of the Insanity Defense Reform Act in New York, "less than one half of one percent [of those arrested] avoided the criminal justice system for mental health reasons ... less than 2 percent of this tiny portion successfully plead insanity." None of those who assassinated, or attempted to assassinate, Robert F. Kennedy '48, the Rev. Martin Luther King Jr., John Lennon, President Gerald Ford or George Wallace, were acquitted by reason of insanity. John Hinckley was the highly publicized exception to a little used rule.

As to the complaint that the defense is the handmaiden to moneyed justice, Caplan cites the 1972 Brawner decision. The opinion established the standard which holds that a person is not responsible for a crime if, as a result of mental disease, he or she lacks the capacity to "appreciate" the wrongfulness of his or her conduct. But the case also made light of a "well guarded secret." According to the opinion, the majority of responsibility cases concern indigents, not affluent defendants with easy access to legal and psychiatric assistance.

The author has little patience with the members of past and present administrations who, with a little study, would see their public stance on the defense for what it really is: political subterfuge, and a hollow avoidance of substantive discussion. "Because the currents calling criminal responsibility into question are so strong," writes Yale Law School Professor Abraham Goldstein, "those who look to criminal law to shore up weakened social supports see the insanity defense as a call to battle." The same kind of Administration thinking that hoped to tamper with the exclusionary rule has allowed the Justice Department to exploit the burst of media attention and attack a straw man.

At the start of the Hinckley trial, polls showed that 87 percent of the public believed that too many murderers were using the insanity plea to avoid jail. Reagan adviser Edwin Meese III, quoted as saying that reform of the defense would help "rid the streets of the most dangerous people... out there," failed to understand what a recent Harvard Law Review article made clear:

"An acquittal by reason of insanity is rarely a ticket to freedom...a person who commits a crime is either responsible enough to deserve punishment or insane enough to deserve commitment."

CAPLAN, reading the fine print and the fictitious rhetoric, cries foul. He is quick to recognize that the attempt, however fashionable, to undercut a defendant's individual rights in the name of "security" or societal rights is at best self-defeating and at worst dangerous.

"Even when there is value gained for value given, the erosion of liberty for the sake of security threatens fundamental principles. When the trade-off is false, as becomes evident in study of the insanity defense, and the law gives up safeguards without any assurance of improvement of public safety, the government takes a step towards tyranny."

To the American public, the Hinckley acquittal became the symbol of excessive, and indulged, violence. To Caplan it is neither a judicial coup or rallying point, just a necessary working of an inviolate standard. Administration fingers, tinkering with the defense, will only reveal an injudicious strong arm.

"Abolishing the insanity defense would mean abandoning the idea on which the Anglo-American system of criminal justice rests--that of man as a responsible agent with free will...By overlooking concerns that a man's will (can be) limited by mental illness, so that he would be unable to choose between good and evil as the criminal law now requires, Attorney General William French Smith...calls for a fundamental change in American jurisprudence."

Those who support the insanity defense argue that it lends moral credence to criminal law. Perhaps the real problem is trying to find a formula that preserves the public's sanity. Put bluntly, acquittals such as Hinckley's insult our gut instincts and our primitive sense of justice. "Is Hinckley's crime," the trial prosecutor asked, "the crime of someone who does not know what he is doing and who is out of control, or is it the crime of someone who has an evil, twisted and perverted mind?" The difference between being sick and depressed, psychotic and merely "sad at Christmas," underscored the trial debate. While the prosecution emphasized Hinckley's act, the defense attempted to show that the illogical, disjointed association between Hinckley's violence and his fantasy world was sign of process schizophrenia.

DEMANDS for reform after the trial were loud, political and, according to Caplan, inconclusive. The hope was somehow to reconcile that natural gut reaction which sees the act, the victim, the murderer and calls a spade a spade with the more informed need to preserve conceptions of human will, avoid the connection between illness and evil, and abstain from seeking the hypocritical solution of committing the sick to prisons that offer no treatment or hospitals that are no better than prisons. Discussion centered on two legal reforms: allowing for a verdict of guilty but insane; and restricting the scope of the defense by limiting judgment to a defendant's criminal intent (mens rea is the proper legal term) at the moment of the crime.

Neither change could move towards a clear resolution of the debate. The contradictions and inconsistencies inherent in each tend only to underline the sensitivity of cases in which mental responsibility is an issue. For a jury, Caplan argues, that is "not able to rule with confidence that a defendant was sane, both 'guilty but mentally ill' and 'guilty but insane' permit the evasion of the hard, unqualified choice between guilty or not guilty usually required by the criminal law." The move towards a double standard of judicial judgment for the mentally ill is tantamount to making constitutional a cynical and callous assessment of the status of a fellow citizen. The proposed mens rea standard (already accepted in certain states) seems ambiguous at best. The question of intent or motivation, separate from the crucial one of illness, is thorny and puts us closer to equating illness with "evil." In any case, restricting a legal rule will hardly deter the actions of those who would normally use it. The convicted ill would only become mistreated, untreated prisoners. The small numbers and type of accused, it seems, must force the debate into less charted ground and away from simplistic solutions. The legal and medical discussion of just how sick sick is will continue.

What could be stopped, of course, is the ability of the sick to purchase firearms. Though John Hinckley was under psychiatric care and taking prescriptive drugs long before the shootings, he succeeded in buying guns on ten different occasions.

At one point, only months before the attempt on Reagan's life, Hinckley was arrested for carrying firearms on a plane bound for Nashville. He was fined sixty dollars, held for a few hours and released. Hours after the Washington shootings, a copy of the Second Amendment, which guarantees (depending on one's interpretation) "the right of the people to bear arms..." was discovered in Hinckley's wallet.

It is an older issue, but no less pressing in the wake of what has recently been characterized as a rash of "insane" political violence. A judicial system that judges the sick and arms the sane simultaneously, without thinking of the two together, may well be the most frightening of judicial delusions.