[Mike Z]

My view on the death penalty is the concept is fair. Do onto other as they would/have do/done on to you. That said, I think the problem is with how we determine guilt. At present there is no 100% way of determining guilt. Everything we do is based on a risk assessment. If we are to maintain a civilize race we need to hold people accountable for their action. When you are part of a society you are aware of the rules however imperfect they are.
To answer you question, as humanly close as possible to zero.