AS HOPES FADES in Atlanta for an immediate solution for the murders of 20 black children in less than two years, a small number of anguished residents have begun organizing "citizens' patrols." In two predominately black housing projects, volunteers have armed -- the youngsters with baseball bats and, where available, the adults with firearms.

Sponsors of the patrol at one projects, Techwood Homes, insist they are "not vigilantes." Their behavior, however, meets the classic criterion laid down by earlier American "vigilance committees": groups organized outside the law to terminate or punish crime in situations where normal police processes appear inadequate.

The appearance of the patrols is an understandable response to the frustration within Atlanta's black community. At the same time, those responsible for the patrols are only adding to the difficulties of Atlanta's already overburdened police. Volatile crowds of project residents, stirred by armed vigilantes, could easily get out of hand. Atlanta police officials have been forced to assign dozens of extra policemen -- including several plainclothes officers taken off the murder investigation -- to monitor the citizens' patrols. That seems a particular waste of the city's limited law enforcement resources, since none of the 20 dead and two missing children are evidently from the area of the patrols.

Let us be plain. Atlanta does not need self-appointed gun-toters. It is not for want of effort that its policemen have failed to prevent additional murders. The recent clashes between some vigilantes and police trying, properly, to disarm them have brought Atlanta that much closer to a breaking point.

Those who have taken up arms beyond the law have done more than threaten the integrity of government. At the same time, they undermine more effective modes of citizen cooperation in the crisis at hand. Thousands of volunteers, for example, have engaged in undramatic, laborious pursuit of possible clues to the murders of the children. These volunteers, working close and supervised fashion with the police, make up the city's real and honorable "vigilance committees."