The Supreme Court yesterday required that in most cases police obtain a warrant before entering a suspect's home to arrest him.

The decision, an extension of the Fourth Amendment protection against unreasonable search and seizure, overrules or clarifies federal law and the laws of over half the states, including Maryland and Virginia. Warrants are already required in this kind of case in the District of Columbia.

Three dissenting justices said the ruling further handicaps police in the performance of their duty.

The decision was a first for the Supreme Court. Warrants have long been required for most searches of a home or business. But in many places, until yesterday, police could simply announce themselves during daylight hours at a home, enter to make an arrest for a serious crime and conduct a limited search.

The court ruled 6 to 3 that only dangerous or emergency conditions justify such a warrantless breach of "the sanctity of the home," "the zone of privacy."

No emergency was claimed in the two New York cases leading to the decision, the court ruled. In one, detectives, believing that Theodore Payton had murdered a gas station manager two days earlier, knocked on the door of his apartment in January 1970 to arrest him. Getting no response, they used crowbars to break down the door and enter. Though Payton was not at home, police found evidence later used to convict him.

In the second case, police went into the home of Obie Riddick, an armed-robbery suspect, after their knocks were answered by Riddick's 3-year-old son. They arrested Riddick, who was in bed, searched his chest of drawers and found narcotics and related paraphernalia. Riddick was indicted and convicted on narcotics charges.

New York law expressly authorized the police actions in both instances. But Justice John Paul Stevens, writing yesterday for the majority, said that while warrantless arrests are legitimate in public places, no law can justify such an intrusion into a home.

The court ruled that the evidence seized by the illegal entries was inadmissible in court and reversed the convictions of Payton and Riddick.

"The Fourth Amendment protects the individual's privacy in a variety of settings," Stevens said. "In none is the zone of privacy more clearly defined than when bounded by the unambiguous physical dimensions of an individual's home -- a zone that finds its roots in clear and specific constitutional terms: 'The right of the people to be secure in their . . . houses . . . shall not be violated.'"

The Constitution "has drawn a firm line at the entrance to the house," Stevens wrote. "Absent exigent circumstances, that threshold may not reasonably be crossed without a warrant."

The decision did not define "exigent circumstances." Generally, however, police in "hot pursuit" or facing an immediate physical danger are said to be in such circumstances.

Practically, the decision means that a police officer with probable cause to believe someone has committed a crime must present his information to a local judge or magistrate empowered to issue the warrant before making an arrest inside the suspect's home. A policeman without a warrant can enter someone else's home where the suspect happens to be visiting or hiding.

Justice Byron R. White, dissenting with Chief Justice Warren E. Burger and Justice William H. Rehnquist, said the ruling may "severely hamper effective law enforcement. . . . The policeman on his beat must now make subtle discriminations that perplex even judges in their chambers. . ."

Police "may refrain from making the arrest, thus creating the possibility that a dangerous criminal will escape into the community," the dissenters said.

Current protections -- the need for a police announcement, probable cause and daylight hours -- are sufficient to eliminate the need for a warrant, they said.

In another criminal case yesterday, the court ruled in favor of law enforcement authorities by an 8-to-1 vote. With Justice Thurgood Marshall dissenting, the court ruled that a defendant's failure to cooperate with police in tracking down narcotics peddlers can legitimately be a factor in imposing a stiffer sentence.

The case, Roberts vs. U.S., arose in the District of Columbia.