USA:
Don't ignore larger issue

It is every prosecutor's worst nightmare to convict an innocent person. Yet true "exonerations" are extremely rare events. The term "exonerated" should be reserved for those few people who are literally innocent. They didn't do it, they weren't there, and they didn't hold the victim down while someone else stabbed him.
A recent study claimed that there were fewer than 400 "exonerations" during the past 15 years, although some of those were cases in which the system simply gave up prosecuting a far cry from actual innocence. More important, those several hundred cases came out of a universe of millions of arrests, meaning the problem of wrongful conviction is more episodic than epidemic.
No one wins when an innocent person is convicted. There should be a mechanism for compensating people who were innocent yet imprisoned. But America's prosecutors spend their professional lives trying to make sure that does not happen.
It was prosecutors who pioneered the use of DNA in courtrooms, usually over the fevered objections of criminal defense lawyers. Now many of those same lawyers herald the use of DNA, but only if it clears their clients.
A far-reaching DNA bill that Congress recently passed promises hundreds of millions of dollars to provide DNA testing. Much of this legislation is badly needed, not just to exonerate the handful of people who did not commit the crimes of which they were accused, but, more important, to solve the hundreds of thousands of rape cases in which untested DNA sits on police-evidence shelves across the USA.
Yet that same law forbids the inclusion into the national data bank of DNA information swabbed from the mouth of a suspect unless the person was convicted. That makes as much sense as refusing to enter fingerprints into the national automated fingerprint system. While we read about the few exonerated by DNA, "cold case" convictions from DNA tests some from people who were never convicted have become so common that they no longer constitute news.
If we are really looking for a truth-based justice system, and not just a gladiatorial adversary model, we want as much truthful information as possible.
(source: Guest Editorial, USA Today; Joshua Marquis, a district attorney in Astoria, Ore., speaks across the USA and overseas on criminal justice issues)