Considering how much effort goes into gathering evidence, making a case, and all the ways it can be challenged and appealed, not nearly as many as you might think.
My dad was a journalist reporter that focused primarily on wrongfully convicted persons. In less than ten years he wrote stories about at least four people wrongfully convicted who eventually were released. That's just my area. Might sound like a small number but even one is unacceptable. These are people's lives we're talking about.
There's always going to be mistakes. Punishing them when they occur is great, but saying that even one is unacceptable just isn't feasible.
Four really is a great number when you're talking thousands.
We're talking forty plus years combined that just these few people were incarcerated, then compensated by the state upon release. You're fine with your tax dollars going to waste like that?
It's inevitable. Trying to completely eliminate false convictions would be like trying to stop fish from being wet. It may well just make things worse.
Four really is a great number when you're talking thousands.