Police Chase Rules Eased by High Court : Law: The opinion limits curbs on unjustified searches until a suspect is in custody. Evidence tossed on the run can now be used by prosecutors.

The Supreme Court gave police more leeway Tuesday to chase suspects on the street, even when they lack evidence that a crime has been committed.

A fleeing suspect is not entitled to 4th Amendment protection against unjustified search and seizure until he is physically in custody, the court said in a 7-2 ruling, and any evidence that he discards during the chase can be used against him in court.

The narrowly worded decision clarifies the court’s earlier attempts to define when someone has been seized by the police. The result is in line with recent court rulings that limit the rights of suspected criminals and provide more freedom to police and prosecutors.

Justice Antonin Scalia, writing for the court, set forth a new and simple rule: A person is “seized” only when he is in the “physical control” of the police or when he submits to a “show of authority” by the police.

In the case from California, the justices were confronted with what has become a common scene in the war on drugs. As a patrol car came upon several young men standing near a car on a street in Oakland, they scattered and ran.

Can the police chase the young men, even though officials do not have a reason to believe the youths are doing anything illegal? Yes, the court said.

Can they stop them and search them for evidence? No, the court said. An officer may not detain or search a person unless he has a “reasonable suspicion” that the individual is violating the law. Merely running away does not supply that suspicion, the court said.

Tuesday’s ruling overturns two recent decisions by state appeals courts in San Francisco and Santa Ana. Last year, these state judges dismissed drug evidence discarded by fleeing individuals on the grounds that police acted illegally by chasing them before they had reason to believe the individuals had committed a crime.

State prosecutors said that the two rulings illustrate the legal confusion over the 4th Amendment’s ban on “unreasonable searches and seizures.” They charged the California courts were in disarray in defining the moment when the 4th Amendment is triggered.

According to the state courts, the 4th Amendment is triggered when police give chase to a person without cause. But the Supreme Court ruled Tuesday that the 4th Amendment is triggered only when the suspect is grabbed by police or stops at an officer’s command.

That difference is significant if a fleeing suspect discards drugs or a gun as he runs. Under the so-called “exclusionary rule,” evidence that is obtained in violation of the 4th Amendment must be excluded from the trial.

Scalia said that it makes no sense to say that a suspect is seized when he runs away.

The mere fact that a police officer is “yelling: ‘Stop in the name of the law!’ ” does not mean the suspect has been seized if he is “a fleeing form that continues to flee,” Scalia wrote.

In the case decided Tuesday (California vs. Hodari D., 89-1632), an Oakland youth had discarded a piece of rock cocaine as a police officer was about to grab him. That evidence could be used against him, the justices said.

Orange County prosecutors also have appealed a state court ruling that dismissed drug evidence discarded by a fleeing suspect in San Juan Capistrano.

Justices John Paul Stevens and Thurgood Marshall dissented from Tuesday’s ruling. They said that they fear the ruling will encourage “coercive and intimidating” conduct by the police.