U.S. District Court Judge Frank A. Kaufman declined this afternoon to act on a motion by the Prince George's County schools to dismiss the NAACP's charge of racial discrimination in the nation's 13th largest school district. Kaufman said the NAACP presentation, which wound up today, was "by a bare margin" enough to continue the civil trial.

Kaufman criticized the NAACP throughout its presentation for failing to provide specific details of its accusations that school board actions during the 1970s increased racial concentrations in the116,000-pupil school system.

In seeking to end the trial without having to provide a defense, lawyers for the board argued that the NAACP had not proved intentional acts of resegregation by the board since Kaufman ordered the sweeping desegregation of the Prince George's schools in 1972. The NAACP contends that the school system never fully implemented the plan.

But without either granting or rejecting the dismissal motion, Kaufman instructed the school board to begin its defense.

At the end of today's session, he cautioned school board lawyers to be prepared, when they resume their defense on Monday, to go into great detail in explaining how they implemented his earlier desegregation order.

"The judge has given us a direction to go forward, that's what we intend to do," said school spokesman Brian Porter. "We intend to lay out every piece of evidence at our disposal to demonstrate that we have done nothing wrong. He said that if we didn't, he would," Porter added.

Kaufman relinquished control over the Prince George's schools in March 1975 after presiding over the implementation of a controversial busing plan he ordered after finding the county guilty of running unconstitutional, dual school systems. Under a 1976 Supreme Court ruling, persons who complain about a system that has been successfully desegregated by court order must show intentional acts by the school board as the cause for further charges of discrimination.

Kaufman said yesterday that the NAACP had raised sufficient evidence to question whether the system was ever effectively desegregated. If it is found that the schools never met the test, intention will not have to be shown for the judge to order more changes in the school system.

"We're not fighting a semantical battle," Kaufman said today. "If there has been unconstitutional segregation, there is an affirmative duty to do a thorough diligent job to keep segregation from sliding back in."