I no longer condone it, under any circumstances. If, as I suspect, there is no afterlife then killing someone is really killing them. The supposition is that they continue to exist in some fashion. I see it differently - a life is destroyed and that is the end of it . I don't believe so.
Capital punishment is arbitrary.
Mistakes are made. We occasionally hear of people released from prison, even death row, because of new evidence coming to light. We can't undo it . Even if errors are extremely rare, I believe any errors are sufficient reason to stop the practice. People can change, at least sometimes.