That DNA evidence that could exonerate you? You don't have a right to it,
says the US Supreme Court.Actually, not being a lawyer or constitutional scholar, I don't know what kinds of evidence you have a constitutional right to when you go on trial, so I'm not going to comment on the correctness of the decision. But legal scholarship aside, two things are obvious:
1) When we try someone for a crime, we want the best, most reliable evidence possible. It's probably reasonably safe to say that most people with at least some wisps of sanity would like our criminal justice system to convict the guilty and acquit the innocent.