One compelling reason to oppose the death penalty is a wish not to give the state that much power over citizens. I well understand the argument in favor of executions and many people richly deserve it but I am a bit inclined to agree with the premise that the government should be limited and not have the power of life and death over citizens. To be honest, I’m about evenly split on the question. For some monsters though, I would like the right to choose their cellmates :)
I don’t see it as power of the state but of the people. Jury trial, jury penalty recommendation.
Is the death penalty a deterrent? Maybe not, but it does guarantee the murderer will not be a repeat offender.
Some crimes are so heinous that to not hand down the death penalty would be an insult to civilized society.