One of the surest ways for a prosecutor to win a criminal conviction is to build a case on eyewitness testimony -- people who tell juries that they were at the scene and that they can point out the culprit. Psychologists who have studied intensively the reaction of jurors to such evidence say that nothing is more persuasive: juries almost implicitly trust those who say they were there.
It is the kind of evidence that can lead to a guilty verdict even if there is practically no other evidence to speak of -- as was the case in the high visibility case of Troy Anthony Davis, executed last month in Georgia for a 1989 murder conviction that was based primarily upon nine eyewitnesses' accounts of what had happened at night outside a fast-food restaurant.
Davis' lawyers were unable to convince the courts, in 22 years of trying, that he was innocent of the murder of an off-duty Atlanta police officer. Their main argument was that seven of the nine eyewitnesses had sworn under oath, since the trial, that they had been mistaken.
But there will be something of an echo of that argument tomorrow morning in the U.S. Supreme Court, as a lawyer for a Nashua, N.H., man, Barion Perry, convicted of stealing stereo equipment out of the trunk of a car parked in an apartment lot, will attempt to persuade the nine Justices that mistaken identifications have reached epidemic levels in the U.S.
In legal papers filed in the case of Perry v. New Hampshire, the Court has been referred to a study done earlier this year by the Innocence Project, an advocacy group, concluding that "eyewitness mis-identifications contribute to over 75 percent of the more than 220 wrongful convictions in the United States" that were overturned on the basis of DNA analysis.
Perry's lawyers will be relying upon a string of Supreme Court rulings in the 1960s and 1970s, declaring that it is a violation of the Constitution's fair-trial guarantee, under the Due Process Clause, to put before a trial jury an eyewitness account if there is a strong indication that the testimony was unreliable, because the testimony was said to be the result of "suggestion" -- either by police, or by circumstances at the scene.
To be clear, there is under those prior rulings no free-standing constitutional right not to be convicted based on a flawed eyewitness account. But there is a right to a fair trial, and the Court considers such flawed evidence to be a threat to fairness. As it remarked in a 1967 decision (U.S. v. Wade): "The dangers for the suspect are particularly grave when the witness' opportunity for observation was insubstantial, and thus his susceptibility to suggestion the greatest."
Recent studies have shown that police are not alone responsible for inducing an eyewitness to ID a suspect. The witness' own characteristics, those of the identified suspect, the conditions at the time on the scene -- all have the capacity to leave in the memory of a witness a scene and an incident that may, in fact, be mistaken. The number of those studies, essentially all drawing the same conclusion, has mushroomed since the Supreme Court's last ruling on eyewitnesses and the Due Process Clause 30 years ago.
The state of New Hampshire, and the federal Justice Department, are trying to head off a new ruling that would expand those earlier precedents so that they would apply to any situation, whether or not police had orchestrated the identification. The rights that are guaranteed to criminal suspects by the Bill of Rights, such as the right to a lawyer and the right to confront accusers, are sufficient to keep such questionable evidence out of court, they have argued.
This post first appeared on Constitution Daily, the blog of the National Constitution Center in Philadelphia.