The Supreme Court, saying state courts had limited power to refuse to extradite people charged with crimes in other states, ruled 7 to 2 yesterday that a California man must be sent to stand trial in Louisiana for kidnaping his children -- even though California courts had awarded him custody.

Justice Sandra Day O'Connor, writing for the court, said the Extradition Act of 1793 did not give one state the authority to determine the guilt or innocence of someone charged in another state.

"The courts of asylum states {in this case, California} may do no more than ascertain whether the requisites of the Extradition Act have been met," she wrote. Those minimal requirements include proper documentation from the demanding state, criminal charges against the person and other essentially procedural matters.

The case began after Richard and Judith Smolin were divorced in California in 1978. Sole custody of their two children was given to their mother with visitation rights to the father. Bitter and complex litigation began in 1979, when Judith Smolin remarried, became Judith Pope and left the state without telling her former husband.

Richard Smolin then sought and received from California courts sole custody of the children -- an order, O'Connor said, that was ignored by Pope. "After securing a California warrant to obtain custody in 1984, Richard Smolin and his father, Gerald Smolin, resorted to self-help," O'Connor said, and picked up the children in Louisiana while they were waiting for their school bus and took them back to California.

"The Popes raised the stakes," O'Connor said, by accusing the two men of kidnaping. Louisiana officials then charged the men and demanded that they be delivered up for trial.

The men appealed, saying the allegations were based on a fraudulent affidavit by Judith Pope. The California Supreme Court refused to turn the men over, saying they had not been "substantially charged with a crime."

O'Connor, writing for the court in California v. Superior Court of California, San Bernadino County, said neither the Extradition Clause of the Constitution nor the 1793 act allows California to review the underlying charges.

An extradition proceeding, O'Connor said, "is neither the time nor place for the Smolins' arguments that Judith Pope's affidavit is fraudulent and that the California custody decrees establish {the father} as the lawful custodian under the full faith and credit provision of the federal Parental Kidnaping Prevention Act of 1980."

There was, she said, "nothing to suggest that the Smolins are not entirely correct in all of this . . . . If the Smolins are correct," she said, "they are not only innocent of the charges made against them, but also victims of a possible abuse of the criminal process.

"But, under the Extradition Act, it is for the Louisiana courts to do justice in this case, not the California courts," she said.

Justice John Paul Stevens, joined in dissent by Justice William J. Brennan Jr., said the majority was needlessly providing "estranged parents with an inappropriate weapon to use against each other as they wage custody disputes throughout this land."

Stevens said the majority was adopting an "overly restrictive view" of the powers an asylum state has. The law "does not foreclose a summary inquiry into whether the crime charged is legally possible," Stevens said, concluding that, in this case, it was not legally possible for the father, having been granted custody, to kidnap his children.

In another case decided yesterday, the court ruled 5 to 4 that the need for prison discipline may outweigh the First Amendment rights of prisoners to exercise their religious beliefs.

The court, in an opinion by Chief Justice William H. Rehnquist, said New Jersey prison officials did not violate the rights of a group of Muslim prisoners when, citing security considerations, officials prevented them from attending services on Friday afternoons.

A federal appeals court had ruled that prison officials had to show that "no reasonable method exists by which {the prisoners'} religious rights can be accommodated without creating bona fide security problems."

The high court reversed. "By placing the burden on prison officials to disprove the availability of alternatives" to barring attendance at the services, Rehnquist said, the appeals court "fails to reflect the respect and deference that the United States Constitution allows for the judgment of prison administrators" who, he said, "acted in a reasonable manner."

Brennan, joined by Justices Thurgood Marshall, Harry A. Blackmun and Stevens, dissented from the decision in O'Lone v. Estate of Shabazz.