The United States Supreme Court has opened a crack in the exclusionary rule - the fence of law that for 70 years has blocked use of illegally obtained evidence in federal trials.
Yesterday the high court ruled that evidence which would have inevitably surfaced can be used by prosecutors, even if it was turned up by police who acted improperly.
''Anything less would reject logic, experience, and common sense,'' Chief Justice Warren E. Burger wrote in his opinion.
By allowing this ''inevitable discovery'' exception to the exclusionary rule, the Supreme Court put its stamp of approval on a principle many federal appeals courts already use when reviewing criminal cases.
''This is a significant (decision) that should be of substantial assistance to law enforcement,'' says Rex Lee, solicitor general of the United States.
The case at issue involved the conviction of Robert Anthony Williams, in Iowa , for the 1968 murder of a young girl.
Williams, when first arrested on suspicion of the crime, was convinced by police to reveal the location of the girl's body, which was by the side of a gravel road about 16 miles from Des Moines. But in 1977, the Supreme Court ruled that this action was illegal, since it violated Williams's right to have a lawyer present during questioning.
The high court threw out the conviction, and told Iowa prosecutors to try again. They did - this time arguing that the crucial evidence of the body would have been found anyway, since police had begun a thorough search of the area.
Lower courts didn't agree with this argument. But yesterday, by a 7 to 2 vote , the Supreme Court did. Williams now faces a third trial.
The exclusionary rule, since it was first outlined by the Supreme Court in 1914, has held that illegally obtained evidence could not be used in trials. Because it results in the throwing out of perfectly good clues, opponents say it benefits only the guilty, not the innocent. It also adds another layer of complexity to the US legal system, opponents say.
Civil liberties lawyers respond that it is a crucial protection against abuses by the police.
In yesterday's ruling, Chief Justice Burger agreed the major purpose of the exclusionary rule was to deter police misconduct. But he said if the evidence were to be discovered anyway, ''then the deterrence rationale has so little basis that the evidence should be received.''
This decision represents a relatively small crack in the exclusionary rule. The number of cases affected will not be large, notes Charles Sims, an lawyer for the American Civil Liberties Union. But he is concerned ''inevitable discovery'' may prove difficult to define.
Still to come is the Supreme Court's decision on another, larger question concerning exclusion of evidence - the so-called ''good faith'' exception.
Under this exception, defense lawyers would have to prove that police knew they were acting illegally when collecting evidence, and went ahead anyway. It would significantly narrow the exclusionary rule of law.
The court also handed down a 9-to-0 decision that should make it easier for localities to enforce drunken-driving laws. Justices struck down a California ruling that said breath samples must be preserved. The state can now legally use the Intoxilyzer breath analysis machine, which prints results but does not save samples.