THE ACTIONS OF New York's subway vigilante hold a visceral appeal but ultimately constitute a false solution to the problem of American crime. Vigilantism and good citizenship are not the same thing.

Bernhard Hugo Goetz, the man who has come forward and identified himself as the vigilante, has apparently told police that he believed himself about to be robbed, produced a gun, shot his presumed assailants and left at the first opportunity: a neat and clean example of private justice -- except that we are a society of public justice.

The difference between private and public justice is more than semantic. Private justice defines individuals as wronged parties and places upon them the burden of seeking redress. Acts of revenge are an example of private justice, which best serves the strong.

Public justice serves both weak and strong. It defines society as the wronged party and sends the state to court to obtain justice for the individual member who has been wronged. Criminal prosecutions are examples of public justice.

Those who see the subway shooting as an understandable and justifiable response to a failed system of public justice misunderstand. Our system of public justice is based upon the notion that the police, the courts and the corrections system are institutions of last resort and that the primary responsibility for crime prevention remains with the community. At the time our Constitution was written, this responsibility was clear, because the police as we know them did not even exist.

Both the police and prisons were 19th century inventions. The efforts of Sir Robert Peel, for whom the British Bobbies were named, led to the establishment of the first modern police in England in 1829. Peel conceived of a "citizen police force" as a less bloody alternative to military suppression of the urban riots that accompanied the industrial revolution.

During that era, hordes of rural people moved to London and other big English cities in search of jobs, but soon found that there was no work and, worse, that there was no food. Hungry and frustrated, they rioted, and the only means of quelling the riots was to call out the military, who responded as they were trained: by shooting the rioters. Peel reasoned that a force composed of civilians would respond in a more humane way to the plight of their fellow citizens. He was right, and his model of civilian police soon spread to the United States.

When it did, the crime suppression job of the police was secondary to their main task of preventing and responding to civil disorder. Only when some semblance of quietude and stability fell upon American cities did police become crime fighters. Even when that happened, the chores of the police were minimal. Because most crime occurred in areas populated by the poor and powerless, the police did not work very hard.

In the more established communities, the major forces of law and order were not the police. Instead, they were -- and still are -- those things that define a community: a sense of commonality, loyalty to one's group, a desire to remain a part of that group and a desire to protect it against threatening influences.

We see that still in rural America and in the ethnic neighborhoods that dot our big cities. In New York City, where I was a police officer, the police do not prevent crime in Chinatown, Germantown, Little Italy or the West Indian sections of Brooklyn. Crime is prevented -- and it is prevented -- there by the cohesiveness of the people who live in those neighborhoods. It is prevented by their willingness to stand up for each other; by their fears of being condemned by their neighbors, of losing their places and their reputations.

Where neighborhoods are relatively stable and where people share common concerns, that level of community is high and crime rates are low. Urban crime rates were probably never lower, in fact, than during the years in which neighbors shared the burdens and rewards of the Great Depression, the Second World War and the stability and prosperity of the 1950s. During those years, the police convinced themselves and the public that effective law enforcement accounted for low crime rates.

Since the 1960s, we have learned that this approach was wrong. When crime rates started to soar in the mid-'60s, the police promised that more personnel would provide a cure. They got more officers and more resources, but crime continued to rise. Researchers began to study police work and suggested that it was wrong to think of officers as "law enforcers," because they spent little of their time -- something around 10 percent -- dealing with crime-related matters.

Evaluations of traditional police crime-fighting methods and strategies reported that most had little or no impact on public safety. The Police Foundation conducted an experiment in which all routine car patrols were halted in some Kansas City neighborhoods for a year and found that neither the public nor the criminals even noticed their absence.

Ironically, one of the few places where it was shown that police could make a difference was on the New York subways. There, massive increases in manpower in the mid-'60s put at least one police officer on every train and every station during the evening and early morning hours. Subway crime virtually went away. Such high police visibility has since fallen victim to austerity budgets brought on by New York's fiscal crisis.

What began during the 1960s and continued until a couple of years ago, it now appears, is that crime increased as social change -- including the coming of age of the baby-boom generation -- challenged and transformed stable old neighborhoods. Anonymity, conflict and a desire "not to get involved" replaced community and cooperation as the order of the day in American cities. Kitty Genovese, who was murdered in Queens in 1964 as dozens of her neighbors literally turned their backs, died not because of any failure of the police, but because nobody wanted to get involved enough to call the police to the scene.

Nothing is more frustrating to the cause of law enforcement than the citizen who fails to call the police promptly when a crime is committed, or the witness who does not tell the police what he or she knows. These are the failings that have emboldened criminals to act with seeming impunity.

When police chiefs found that marginal increases in police personnel had little effect on crime rates, and that taxpayers were unwilling to pay for the massive police hirings necessary to achieve any real results, most police forces reverted to rebuilding the community. They enlisted citizens in anticrime efforts, organizing groups of blockwatchers and crimestoppers and assisting in the formulation of volunteer citizens' patrols. The police have built bridges between themselves and citizens and have helped neighbors come together out of mutual concern over crime.

Where once neighbors did not know each other, they have been encouraged by police to become their brothers' keepers, to keep an eye out for each other and to call police when things are awry. In recent years, crime rates have decreased in part, I am convinced, because of the new sense of community that characterizes many of the formerly most crime ridden areas of American cities.

By the same token, people with a sense of community, with a stake in the status quo, do not, for the most part, commit crimes. But what about kids who have no such stake and what about places where no sense of community exists? The "vigilante" did not shoot four middle-class undergraduates. He shot four black teen-agers from South Bronx in a subway car full of strangers.

It is virtually impossible to build any sense of community in the subways. In New York, where 3.2 million people ride them every day, the subways are nobody's neighborhood. There is demonstrably no sense of community in subways where some riders routinely menace others while a far larger number of bystanders does nothing. The subways are filled with anonymous people who feel no kinship to each other and who regard late-night subway rides as ventures into a dangerous netherworld shared by strange and fearsome companions.

In such places, private justice like that exacted by the vigilante serves no one well. Is it only fortuitous that none of the other passengers on the vigilante's train was struck by a stray bullet? What must they have thought when the vigilante opened fire? What would have happened had other passengers -- or one of the young men he shot -- also been carrying guns?

The vigilante's life has not been changed for the better by the events of that night. Nor have the subways been made safer by his actions. But how many frightened people have been encouraged by his example and the resulting ill-considered adulation to carry guns into the subway? Will things go as smoothly the next time a subway rider plays Charles Bronson? What, one must ask, if everyone followed his example?

The real lesson of the vigilante is not that our system of public justice has failed, but that it has limits. The subway shooting and the response to it are not signals that private justice is appropriate: it is a warning that we must redouble our efforts to make certain that the system of public justice works.

The best way to do that is to create that sense of community and that stake in the future that so many of us enjoy. Where we cannot or will not do that -- as in the cases of the New York subways and the young people who populate our most devastated and conflicted areas -- we must rely on the police.

But, we cannot do so half-heartedly. In the case of the New York subways, if the police are to have any meaningful effect on crime, we must be willing to pay for what worked in the past: we must put an officer on every train and every station. That will not come cheap, but it will be a bargain compared to the costs of vigilante justice.