People arrested by police without warrants generally must receive a court hearing within 48 hours to determine the arrest's validity, the Supreme Court ruled by a 5-4 vote Monday.

The court's four dissenters said waiting 48 hours is too long and that such a hearing should be required immediately after an arrested individual is booked.Justice Sandra Day O'Connor, writing for the majority, said a 48-hour period was deemed "constitutionally permissible."

Justice Antonin Scalia, considered the court's most conservative member, was one of the four dissenters.

"Hereafter, a law-abiding citizen wrongfully arrested may be compelled to await the grace of a Dickensian bureaucratic machine, as it churns its cycle for up to two days - never once given the opportunity to show a judge that there is absolutely no reason to hold him, that a mistake has been made," Scalia wrote.

The court in 1975 ruled that people arrested without warrants are entitled to "prompt" hearings to determine whether the constitutionally required probable cause existed for the arrest.

But the court never before had said exactly what it meant by "prompt."

Writing for the court Monday, O'Connor said such hearings generally must be provided within 48 hours.

If more than 48 hours pass before a hearing is granted, she said, "the burden shifts to the government to demonstrate the existence of a bona fide emergency or other extraordinary circumstance."

O'Connor was joined by Chief Justice William H. Rehnquist and Justices Byron R. White, Anthony M. Kennedy and David H. Souter.

Joining Scalia in dissent were the court's three most liberal justices - Thurgood Marshall, Harry A. Blackmun and John Paul Stevens.

The justices also rejected an appeal by a convicted murderer who said he was denied a fair trial because two prominent, private lawyers helped the prosecutor.

The decision sent back to a federal appeals court a "class action" civil rights lawsuit against Riverside County, Calif., by Donald Lee McLaughlin.

He sued county officials in 1987 over the county's policy of providing probable-cause hearings for people arrested without warrants.

Most arrests required quick police action and are not accompanied by previously obtained court warrants. It is for those arrests that such hearings are required.

And in Riverside County, those hearings are provided within 48 working hours - excluding weekends and holidays.

The justices also ruled that workers may be barred from suing their bosses for alleged age bias if the employees previously agreed to submit such claims to binding arbitration.

Some interest groups had told the court such a decision could affect millions of workers. But the court said Monday it was deciding a relatively narrow issue that directly affects the securities industry.

By a 7-2 vote, the justices blocked a federal lawsuit by Robert Gilmer of Charlotte, N.C., who was fired at age 62 by a securities firm and replaced by a 28-year-old woman he helped train.

Justice Byron R. White, writing for the court, said the federal Age Discrimination in Employment Act does not foreclose the enforcement of agreements to arbitrate age bias claims.

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Other decisions

- Agreed to review a ruling the Bush administration says could lead to a flood of young men seeking asylum in the United States from war-torn countries.

- Agreed to consider letting federal agencies ignore the impact on endangered species when they support projects in foreign countries.

- Agreed to review two Alabama disputes centered on the rights of black voters in Etowah and Russell counties.

- Left intact a Tennessee law that lets private lawyers representing crime victims help prosecute criminal defendants.

- Refused to kill a lawsuit that charges Conrail with illegally monopolizing shipments of newsprint from Canada to mid-Atlantic states.

- Left intact a ruling that said Mississippi juries must be told whether convicted killers would ever be eligible for parole if sentenced to life in prison rather than death.