But as Ron Sider noted in The Early Church on Killing (Baker Academic, 2012), those Fathers who discussed capital punishment found it unthinkable that a follower of Christ could take a life, even as part of a judicial sentence. Lactantius said that a Christian should not even accuse someone of a capital crime, "because it makes no difference whether you put someone to death by word or by sword since it is the act of putting to death itself which is prohibited." Origen, recognizing that capital punishment had a place under the Old Covenant, drew a stark contrast between the law of Moses and the law of Christ. Christians, he said, cannot "condemn [someone] to be burned or stoned." Tertullian asked whether a Christian could be a civil magistrate and concluded that believers must avoid "sitting in judgment on someone's life."Way back when, sociopaths were exiled or killed or died in the course of short, brutal lives. In the modern era, non-criminals, including crime victims, have to come up with $20K/yr per prisoner to keep sociopaths clothed, housed and fed and protected behind high walls from extra-judicial retribution.
The linked article draws a parallell with slavery, another institution which was said to be unworkable with Christian praxis. People with very low marginal product used to be slaves, because otherwise they were vagrant beggars. When they got sick or the weather got too cold or they couldn't find food, they died. Then we outlawed slavery and gave low marginal producers welfare so they wouldn't die. Now, the poor are obese and have children they can't afford.
These debates only take place in that interregnum between the institution of the welfare state and the point at which net consumption outpaces the capacity or the will of net producers to fund it. After that, what's old is new again and these debates don't happen.