Lie-detector evidence can be banned from trials, the Supreme Court ruled Tuesday, citing concern over its scientific soundness. But the justices left open the possibility that polygraph results might have to be allowed in some cases.
"There is simply no consensus that polygraph evidence is reliable," the court said, rejecting 8-1 a California airman's claim that he had a constitutional right to tell a court-martial jury that he passed a lie-detector test.The ban on use of lie-detector results in military trials is a valid means "of advancing the legitimate interest in barring unreliable evidence," Justice Clarence Thomas wrote for the court.
Some courts allow the use of lie-detector results in criminal trials, but most state and federal courts ban it. Tuesday's ruling allows each of those courts to continue its own policy.
But four justices among the eight-member majority said a future case might present a more compelling argument that some defendants have the right to use favorable polygraph results.
Writing for the four, Justice Anthony M. Kennedy agreed that the military rule did not violate the Constitution's Sixth Amendment right to present a defense. "I doubt, though, that the rule of . . . exclusion is wise, and some later case might present a more compelling case for introduction of the testimony than this one does," he said.
He was joined by Justices Sandra Day O'Connor, Ruth Bader Gins-burg and Stephen G. Breyer.
Justice John Paul Stevens dissented from the overall ruling, saying it "rests on a serious under-valuation of the importance of the citizen's constitutional right to present a defense to a criminal charge."