The Supreme Court ruled Monday that police who want to look for drugs or evidence of other crimes do not have to first inform public transportation passengers of their legal rights.

The ruling gives police guidance on how to approach and search passengers, a case with renewed interest as officers seek out possible terrorists on public transportation.

Justices rejected arguments that passengers, confined to small spaces, might feel coerced.

The court ruled 6-3 that officers in Tallahassee, Fla., were within their rights as they questioned and searched two men aboard a Greyhound bus in 1999.

Justice Anthony M. Kennedy, writing for the majority, said the passengers did not have to be told that they didn't have to cooperate.

Three officers boarded the bus, bound from Fort Lauderdale to Detroit. One officer introduced himself to Christout to be packets of cocaine.

"It is beyond question that had this encounter occurred on the street, it would be constitutional. The fact that an encounter takes place on a bus does not on its own transform standard police questioning of citizens into an illegal seizure," Kennedy wrote for the court.

Drayton and Brown were convicted and sentenced on drug charges.

The 11th U.S. Circuit Court of Appeals ruled the cocaine should not have been admitted as evidence, because the officers failed to tell the men they were not required to cooperate. That court said the encounter violated the Constitution's ban on unreasonable searches and seizures.

Monday's ruling overturns that decision.

In a dissent, Justice David H. Souter said that three officers "pinned-in" passengers on the stopped bus.

"The situation is like the one in the alley, with civilians in close quarters unable to move effectively, being told their cooperation is expected," wrote Souter, who was joined by Justices John Paul Stevens and Ruth Bader Ginsburg.

He said because of terrorist concerns, airplane passengers know they must submit to searches.

"The commonplace precautions of air travel have not, thus far, been justified for ground transportation," Souter wrote.