IT CUTS BOTH WAYS: DNA evidence gets lots of press as a way of exonerating the innocent. But in the long run, DNA evidence will cut against defendants, as it did in this case. First, it'll make many convictions factually bullet proof. Second, in cases were DNA makes factual innocence a non-issue, procedural error won't matter very much. For courts, procedural error roughly correlates to factual error; we spring bad guys for procedural errors to deter factual errors that might convict good guys. That deterrent loses value when scientific evidence gives an independent and far more reliable means of preventing factual error.