Innocence is a project worth pursuing in the land of the free

It is just possible, that Tuesday 4 October 2011 will go down in American legal history. Not for an especially lurid crime, the capture of a most wanted criminal, or a historic ruling by the Supreme Court – but because on that day, in separate corners of the country, three men were released from prison after spending more than six decades behind bars, each convicted of a murder he did not commit.

In Austin, Texas, Michael Morton walked free, exonerated by new DNA tests of killing his wife in 1986.

In Chicago, Jacques Rivera left Cook County Jail, having been convicted in 1990 of a gang-related murder on the basis of false evidence from the sole witness to the crime.

In Los Angeles, the 37-year old Obie Anthony – amazingly bearing no grudges – saw his 1994 murder conviction overturned, after it was shown conclusively that the star witness in his case (a pimp) had lied after cutting a deal with prosecutors.

The cases were connected in only two respects. Each was a shocking miscarriage that exposed deep flaws in the way the criminal justice system works in the United States. And each of the three men could thank for their release an independent, non-profit body called the Innocence Project, working on the assumption – so easy to articulate but often so hard to translate into deed – that the law must acknowledge when it has made a mistake.

Indeed, Amanda Knox, a woman who knows how hard-won such an acknowledgement can be, has professed her own desire to work for the Project one day. No one knows exactly how many wrongful convictions occur in the US every year, but studies suggest anywhere from 2 to 5 per cent of the country's overall prison population of over 2 million – ie, anywhere between 40,000 and 100,000 people – may be innocent.

Suffice it to say that since the Project was founded in 1992, more than 250 people have been exonerated through DNA testing, including 17 under sentence of death.

The Project is currently working on 300 active cases, but these plainly are but the tip of an iceberg of error.

On Tuesday, three cases at least were brought to a happy end.

But the manifold shortcomings of the system will continue – starting with eyewitness mis-identification, responsible for three quarters of the miscarriages of justice taken up by the Project and subsequently corrected by DNA evidence.

In what may be a landmark decision, the New Jersey Supreme Court issued new rules in August, making it far easier for defendants to mount a challenge to such evidence and the methods and circumstances under which it was obtained.

But not only can dubious evidence be manufactured – solid evidence can be suppressed.

Take the Michael Morton case, in which prosecutors withheld a statement by the couple's son, saying that the father was not the killer.

Then there is the surprisingly widespread problem of false confessions, whether extracted by police intimidation or as part of a plea bargain struck by a defendant with prosecutors in return for a shorter sentence.

Other factors that can put an innocent man behind bars include incompetent and ill-paid publicly appointed defence lawyers and the use of informants and jail stool pigeons, many of them (as in the case of Obie Anthony) only too ready to provide suitably damning evidence in return for a reduction in their own term.

It is not always easy to persuade public opinion, obsessed with "law and order" and "putting bad guys where they belong", that a miscarriage of justice has taken place.

At which point enter the Innocence Project.

Founded in 1992 as part of the Cardozo School of Law in New York City, it is an independent, non-profit body, which was originally set up by two lawyers, Peter Neufeld and Barry Scheck.

Ironically, Mr Scheck first became famous as a member of the defence team at the 1994/1995 trial of OJ Simpson not, most people might say, the most obvious vindication of the need for an Innocence Project. But the organisation has flourished and is now spearhead of a worldwide Innocence Network, embracing 55 affiliated organisations in the US and beyond.