of course mistakes have been made, and will be in the future. the reality is that those mistakes have NOT resulted in an innocent person being executed, nor will they ever.
With all due respect, how can you be so sure that all those executions never even once included an innocent person? I agree that an extremely high percentage of executions were performed on guilty persons. But, really, unless you can look into people's minds, memories, you cannot honestly make the statement you just made. That requires god-like powers.
I am a pro too. But obviously our justice system is not perfect. How can it be? We are only human and we make mistakes. Our justice system is GOOD, yes, but not perfect. And if something is not perfect, mistakes can and will be made. Maybe it hasn't happened YET. Even that, I doubt. A mistake will be made and, I believe, has been made, once or twice.
Just my opinion.
Having said that, I now take a step back. I believe it has happened once or twice that someone was executed for a crime he didn't commit. But I also believe that that person was guilty of other crimes. Usually, someone who commits 1st degree murder already has a history of felonies. So even if he was innocent of the crime that got him a death sentence, he's still a criminal. So, yes, maybe he got a punishment that was a little bit worse than he "deserved". I can't say I feel too bad about that. It seems to happen much more often that criminals get punishments that are a lot LIGHTER than they "deserve". So if a criminal gets the DP for a crime he didn't commit, I can't say I feel bad. He was a criminal already. He just got a punishment that was maybe a "little bit too harsh".