I grew up and lived in VA most of my life. VA is a very traditional Southern State and loved the Death Penalty. The problem came up back in the late 90's and early 00's it was discovered that a very large number of people suffering from such disadvantages as autism, mental illness, and being the wrong shade of "not white" while in the south, had been put to death. The problem is not that a high degree of certainty is needed, the problem is people. The attorneys, the judges, the juries, nobody involved tried to stop it. It was a system designed to come to one conclusion and that was that.
Until the system has real oversight and consequences I can not support it. Life in prison is expensive, but if we screw it up we can at least let the person go and write a big check. Sure, they lost 10 years and may be institutionalized, but they aren't dead. Can't even try to set it right if you kill the wrong person.