A Prince George's County school system's practice of transferring teachers to achieve racial balance is constitutional, a federaljudge now says, and it can be continued. This is an important response to a gratuitous suit by the Justice Department. The department had contended that the system was violating the law by assigning teachers to schools according to race, discriminating against white teachers in favor of black teachers with less seniority. But Judge Frank A. Kaufman went to the roots of the county policy to determine that it remains a valid way "to eradicate the vestiges of unconstitutional segregation in the Prince George's County public schools."

There is a difference between the justifications for continuing the county policy and the precise way in which it is carried out. While ruling in favor of the county's reassignment policy, the judge did say that the county's goal that no fewer than 30 percent of a school's faculty be composed of minority teachers is "unrealistic." Judge Kaufman and lawyers for the school board will be meeting shortly to determine what the right percentage should be. This is a sensible way to respond and adjust.

The Justice Department had argued that the transfer policy was unnecessary because Judge Kaufman had ruled in 1983 that the county's schools were adequately integrated. But in those proceedings the judge never said that the school system had fulfilled all its responsibilities to maintain the desegregation already achieved. With respect to teacher assignments, he found in that 1983 decision that "there presently are no vestiges of past racial segregation." But he said it with the understanding that the system would continue its policy of keeping black-white ratios on faculties within certain ranges. He was not offering a cue for backsliding.

That said, it is true that no school desegregation plans should run forever. But the conditions for ending these sanctions still need to be worked out. Instead of jumping unnecessarily on school systems struggling with the most difficult aspects of this question, the Justice Department might more usefully work with the courts to develop acceptable standards for dissolving desegregation orders. For the present, the teacher transfer policy in Prince George's is serving a salutary purpose. Judge Kaufman was right to leave it in place.