We seem to go over the same ground; the opponents talk about fallibility, the supporters talk about making the system not-fallible, and neither side seem inclined to reflexivity.
Let's swap roles.
Supporters: a thought experiment. You are the architect of a new justice system, allowed to use any amount of resources or means to prosecute. The only provisions are that the system remains adversarial so you have an opposite with all your powers, and the criteria for guilt remains beyond a reasonable doubt. How will you ensure not just prosecutions leading to the death penalty during your personal career are sound, but as your legacy?
Opponents: a thought experiment. You have a machine which can infallibly discern guilt one hundred percent of the time. If you allow it to be mass produced, every single legal region will have it, and the death penalty will be strengthened/resumed/introduced. But only the guilty will be punished. You are at the manufacturing plant, do you push the button?
Let's swap roles.
Supporters: a thought experiment. You are the architect of a new justice system, allowed to use any amount of resources or means to prosecute. The only provisions are that the system remains adversarial so you have an opposite with all your powers, and the criteria for guilt remains beyond a reasonable doubt. How will you ensure not just prosecutions leading to the death penalty during your personal career are sound, but as your legacy?
Opponents: a thought experiment. You have a machine which can infallibly discern guilt one hundred percent of the time. If you allow it to be mass produced, every single legal region will have it, and the death penalty will be strengthened/resumed/introduced. But only the guilty will be punished. You are at the manufacturing plant, do you push the button?