The U.S. Supreme Court issued rulings this week on the role of federal courts in child-custody cases, suing state judges and on criminal investigations. And it listened to arguments on Central Intelligence Agency (CIA) policies toward firing gay employees.

- Parents may not turn to the federal courts in trying to resolve conflicting child-custody rulings by courts in different states, the Supreme Court ruled unanimously earlier this week.

The justices said a 1980 federal law, the Parental Kidnapping Prevention Act, was aimed only at getting states to cooperate with each other in such cases, and did not envision federal court intervention.

Writing for the court in a case from California and Louisiana, Justice Thurgood Marshall acknowledged that "child snatching" by competing parents is a national problem. He said congressional sponsors of the 1980 law estimated that up to 100,000 children are kidnapped each year by parents unable to obtain legal custody.

But Marshall said Congress meant only to encourage more cooperation among state courts, and did not mean to get federal courts involved.

"Instructing the federal courts to play Solomon where two state courts have issued conflicting custody orders would entangle them in traditional state-law questions that they have little expertise to resolve," Marshall said. "This is a cost that Congress made clear it did not want the (law) to carry."

The case acted on was sparked by the 1979 divorce of David A. and Susan A. Thompson. They were awarded joint custody of their son, Matthew.

In 1980, a California court presiding over the fight for permanent custody of Matthew allowed Susan Thompson to keep physical custody of the boy as she moved to Baton Rouge, La., to become head of the child neurology division of the Louisiana State University School of Medicine.

Susan Thompson began custody proceedings in Louisiana courts, and in early 1981 was awarded permanent sole custody of Matthew. Shortly thereafter, California courts awarded permanent sole custody of Matthew to his father.

David Thompson sued in federal court, seeking a ruling that California courts had the authority to settle the custody matter. But the Supreme Court ruling said the Parental Kidnapping Prevention Act does not authorize such federal lawsuits.

"Should state courts prove as obstinate as (Thompson) predicts, Congress may want to revisit the issue," Marshall said. "But any more radical approach to the problem will have to await further legislative action.". .

- The CIA, entrusted with protecting national security, should have a free hand to fire a gay agent, the Supreme Court was told.

A Reagan administration lawyer told the justices that the agency's decision to dismiss the agent should not be subject to review in federal courts. But the agent's attorney said the CIA director's broad powers over personnel matters do not give him the authority to violate an employee's constitutional rights.

The arguments came in a case involving the agency's 1982 firing of an agent identified in court documents only by the fictitious name of John Doe. The CIA claimed the agent's homosexuality was a security threat.

Solicitor General Charles Fried told the court that the 1947 law establishing the CIA gives the agency's director the power to fire an employee if such action is deemed "necessary or advisable" to protect the interests or intelligence sources of the nation. …