Of the first 250 DNA exonerations, 190 involved eyewitnesses who were wrong, says University of Virginia law Prof. Brandon Garrett. In November, the Supreme Court will return to the question of what the Constitution has to say about the use of eyewitness evidence, says Adam Liptak in the New York Times. The last time the court looked at the question was in 1977. Since then, the scientific understanding of human memory has been transformed. More than 2,000 studies on the topic have been published in professional journals in 30 years. What they collectively show is that it is perilous to base a conviction on a witness's identification of a stranger.
The state of the law is likely to remain jumbled. On the one hand, the high court has said that the due process clause of the Constitution requires the exclusion of at least some eyewitness testimony on the ground that it is unreliable. On the other, judges are told to use a two-step analysis involving the weighing of multiple factors that in practice allows almost all such evidence to be presented to the jury. Barry Scheck of the Innocence Project at the Benjamin N. Cardozo School of Law says what is needed is a new "legal architecture," one in which judges play an authentic gatekeeping role.
For related coverage in The Crime Report, see http://www.thecrimereport.org/news/inside-criminal-justice/2011-08-convicting-the-innocent