WASHINGTON - Police still must warn the people they arrest of their ''right to remain silent'' when questioned, the Supreme Court ruled Monday as it resolved a bitter, 34-year debate over criminal suspects' rights.
The 7-2 ruling gave a new constitutional dimension to the court's landmark Miranda decision of 1966, perhaps the Supreme Court ruling Americans know best.
''Miranda has become embedded in routine police practice to the point where the warnings have become part of our national culture,'' Chief Justice William H. Rehnquist wrote for the court.
''Miranda announced a constitutional rule that Congress may not supersede legislatively,'' he said. ''We decline to overrule Miranda ourselves.''
As a result, police still are required to give the warnings made familiar to generations of Americans by movies and television or else risk getting suspects' confessions excluded as evidence against them.
Suspects must be told that anything they say may be used against them, they can remain silent or have a lawyer's help while answering, and that a lawyer will be appointed to help them if they cannot afford to hire one.
The new decision delighted civil liberties groups and disappointed some law enforcement organizations.
The court, far more liberal 34 years ago than it is now, sought to remedy ''inherently coercive'' interrogations by creating bright-line guidelines in its Miranda vs. Arizona decision. Courts previously had used a ''totality-of-the-circumstances'' test to determine whether a confession or incriminating statement had been given to police voluntarily.
The Constitution's Fifth Amendment says, ''No person ... shall be compelled in any criminal case to be a witness against himself.''
A federal appeals court last year threw the future of those warnings into doubt, ruling that Congress in effect overturned the Miranda decision by enacting a long-ignored 1968 law known as Section 3501.
That law purports to return the law, at least in federal cases, to pre-Miranda days. It says ''the presence or absence'' of any factor such as a Miranda warning ''need not be conclusive on the issue of voluntariness.''
The Richmond-based 4th U.S. Circuit Court of Appeals ruled that the warnings imposed on police by the Miranda decision were never constitutionally mandated.
Monday's decision said the appeals court wrongly ignored the length of time Miranda has been around and the dozens of follow-up Supreme Court decisions it spawned.
''Whether or not we would agree with Miranda's reasoning and its resulting rule were we addressing the issue in the first instance,'' its age and those other precedents ''weigh heavily against overruling it now,'' Rehnquist said.
Steven Shapiro of the American Civil Liberties Union praised the court for upholding the Miranda ruling, which he called ''an emblem of fairness.''
''Doing away with the police warnings would have sent a terrible message about our criminal justice system, that effective law enforcement depends on keeping people ignorant of their rights,'' Shapiro said.
But a disappointed Robert Scully of the National Association of Police Organizations called the Miranda ruling ''a vehicle inviting routine efforts to exclude voluntary confessions,'' and predicted that Monday's decision ''will only increase the amount of litigation on this point in state and federal courts.''
''This case was not about whether giving the warnings made good public policy, which many law enforcement officers support,'' Scully said. ''Rather, it was about the automatic exclusion of incriminating statements if there was a technical violation of the Miranda guidelines.''
Justices Antonin Scalia wrote a scathing dissent, in which Justice Clarence Thomas joined.
Scalia accused Rehnquist, a frequent past critic of the Miranda ruling, and Justices Sandra Day O'Connor and Anthony M. Kennedy of turning their backs on previous rulings in which they had questioned the constitutional underpinnings of the 1966 decision.
Scalia said Monday's ruling stopped short of saying police questioning without Miranda warnings violates the Constitution ''because a majority of the court does not believe it.''
The 4th Circuit court invoked the 1968 law in the case of a Maryland man accused of robbing banks in Maryland and Virginia.
Charles Dickerson of Takoma Park, Md., reportedly made several incriminating statements to FBI agents after being arrested and charged with seven bank robberies. He says the agents did not give him a proper Miranda warning, a claim that was not challenged in lower courts.
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On the Net: For the decision in Dickerson v. U.S.: http://supct.law.cornell.edu/supct/ Click on ''this month's decisions'' or http://www.supremecourtus.gov