THERE ARE plenty of nonviolent offenders who don't have to be kept behind bars. Tax cheats, embezzlers and antitrust violators don't generally pose a physical threat to the public safety, and you probably wouldn't cringe in fear if a copyright infringer passed you in a dark alley. But these crimes are serious: they undermine the public order and impose on property rights, and those who commit them should be punished.

Mayor Marion Barry offered his opinion this week that nonviolent offenders should not be sent to jail. Prison facilities are crowded, he pointed out, and we really need the space for those who are dangerous. There is an element of reason in this suggestion, but more wisdom in the rebuttal from U.S. Attorney Joseph diGenova. Such a policy change, he said, would "send a signal to the criminal community that if they commit a property crime, they won't get time. . . . It's like giving a license to steal."

Most white-collar criminals are already given sentences that do not involve incarceration, the prosecutor pointed out. Other penalties can be devised that are just as effective and don't cost as much as keeping a felon in custody. But there will always be some -- chronic offenders, for example, or elected officials who violate a public trust -- for whom the society wants to retain the option of prison. And some kinds of nonviolent offenders -- burglars are one type -- frequently become violent almost by chance, when surprised or threatened by arrest.

Let's keep the laws on the books with the potential deterring impact of a prison sentence, and let's be realistic about the continuing needs of the corrections system. At the same time, continued efforts to devise alternative sentences should be encouraged. Restitution is a first step. Fines and community service exact a penalty. And various forms of controlled probation and work release have been effective ways of dealing with some offenders. But it is important that these alternatives be real penalties, not cop-outs, and that the victims of white-collar crimes are satisfied that they, too, have received justice. Society is best served when everyone contemplating a crime -- whether it's a million-dollar fraud or a street mugging -- has to think twice about the possibility that he might be punished for it.