A federal judge has agreed to include the Maryland and Prince George's County governments and the state board of education with the county school board as defendants in the school desegregation suit reopened by the NAACP last September.

In granting the school board's request, U.S. District Court Judge Frank Kaufman said the three additional defendants will be necessary parties to any remedy in the case should the court agree with the NAACP that the board is responsible for any segregated conditions that might exist in the system.

None of the lawyers involved in the case expect Judge Kaufman's ruling, announced last week, to have a significant impact on the suit, which is scheduled for trial in February. Neither the state nor county is planning an active role in defending the board against charges that it violated a 1972 court order by failing to desegregate schools, singled out black students for discipline and discriminated in the hiring and placement of minority teachers.

County Executive Lawrence J. Hogan had instructed county lawyer Robert Ostrom to fight inclusion in the suit. County administrator Kenneth Duncan said Hogan feels that the county government has no influence over the policies of the school board other than funding the school budget. Duncan was uncertain as to whether the county would actively defend the suit.

"Right now we're going to take our cues from county attorney Robert Ostrom on this," Duncan said. "Of course Mr. Hogan's position, going back 10 years, is opposed to busing for achieving racial integration , and the fact of the matter is that the busing plan didn't even work. He is also opposed to the idea of a federal court running a local function like this."

"We think it's unfair that we're involved," said assistant attorney general Jim Shea, who represents both the state and state board of education. "At this point we know nothing about the case. We don't take any position because we can't. We don't know who is right," he said. "It's up to them to defend the suit; I have no idea why they wanted us in," he added.

Alfred Scanlon, a lawyer for the school board, said he wanted the new defendants included because the county funds the schools and state laws govern some of the areas of contention in the suit, such as special education. Scanlon said he does not expect any help from the new defendants.