Capital Punishment / Death Penalty

How can a state justify imposing an irreversible punishment?

Capital punishment raises questions about state power, protection, retribution, error and the worth of a person who has caused serious harm. Its irreversibility makes the possibility of wrongful conviction especially consequential. We can ask what purpose is claimed and what evidence supports that purpose. Accountability for serious harm does not remove the need to examine the means used in response.

A question to sit with (optional): What would justify this power, and what consequence of an error could never be repaired?