Seventy years ago, in a book called Convicting the Innocent, the Yale Law School professor Edwin Borchard produced a classic study of how the wrong person gets sent to prison or to death. The hapless innocents Borchard profiled included a coal miner and a doctor, Central European immigrants and American blacks, an unemployed religious visionary and an Algerian john named Frenchy. In those days exoneration was almost always a matter of luck—occasionally, for example, a supposed murder victim would turn up "hale and hearty" sometime after the alleged murderer landed in the penitentiary. Today, thanks to DNA evidence (when it is available), wrongful convictions can be reversed more confidently than ever before. And that confidence allows us to analyze the reasons for such convictions with greater certainty than Borchard or his contemporaries could.
Yet what is striking about the death-penalty convictions overturned recently (a hundred have been reversed in the past thirty years) and about other cases in which DNA evidence belatedly showed the accused to be innocent is how clearly the convictions rested on the same flawed foundations that Borchard identified. As in Borchard's day, what tends to do in the wrongly convicted is the kind of evidence that seems clinching, that often is clinching—namely, eyewitness identifications and confessions. But the human memory is not a video recorder; eyewitness testimony is notoriously flawed. And although most of those who confess are guilty, people can and do confess to crimes they did not commit—sometimes because they are coerced; sometimes (more often) because they are bewildered, frightened, or exhausted; sometimes because they are children, or adults with the mental capacity of children; sometimes because their interrogators have presented them with plausible scenarios in which they might have committed the crimes unknowingly—while blacked out, for instance, or while in the grip of another personality.