it was because we decided to move to rehabilitation.
Think of it as secular redemption; there is no secular version, so the best we ask for is "say you don't do it again and give us evidence."
Problem was, what's good evidence? Not murdering somebody when you're in a high-security prison? That's a pretty low bar for something that has a pretty fat-tailed risk if you release somebody. So they tended to sit behind bars for a long, long time.
Right. Being in prison for 40 years is merciful. Esp. when you get out at age 62, haven't held a job, and don't even have social security to fall back on, no family because parents are dead and at age 20, when you did the crime, you didn't have wife and kids. (If you had, there'd be a lower risk of doing the crime.)
Then the pendulum shifted, the DP came back, and the reason was easy. Not revenge. Just elimination.
When I set a mouse trap to dispose of a mouse, I don't chortle and say, "Take that, foul vermin, destroyer of insulation, purveyor of fecal pellets, conveyor of disease! I have got my revenge on thee, o roden most vile!" No, I pick up the thing and throw it away, glad to be rid of it but wondering if there are any more inconveniences to be rid of.
When teachers get the truly problematic kid out of their classrooms, they don't think, "Aha! I have wrought my revenge!" Some may think rehabilitation. Most are just glad to have the problem gone so that they don't have to deal with it any more. Executing somebody 10 years after they killed somebody is hardly "a policy based on anger and emotion."
Same with death penalty. Or drug dealers. Or the irritating guy who insists on playing his music at 100 dB each Saturday because he thinks that it makes the block more festive. Even if your thing is alternative rock, classical music, hip-hop, or salsa, you get R&B. Or whatever. The point's clear. The immature seek vengeance; most just seek peace and elimination of the problem so we can move on.
The Biblical admonition is fairly clear. Israel was to be a holy, righteous people. Having a killer in their midst defiled them. If it was by accident, there was a place to be set up where the accidental killer couldn't be touched. There was to be no mercy for the guilty. *However* punishment was left to the family, and the family could work out its own deal. If the murderer killed the prime breadwinner, an important person, then killing the killer leveled the score in a fairly purely economic way. You kill somebody, your clan will suffer. Don't do it. (Deterrence.) At the same time, if the murdered person was low ranking, his net value could be made up in some other way and the clan made whole.
Since that's how justice was often meted out--on a communal or collective basis, where it wasn't the individual's guilt that mattered but making sure the other clan or tribe suffered proportionately, in a way this actually made life a bit more fair. Westerners still are WEIRDed out by this idea when they see it--take how justice is negotiated in some traditional Arab societies, with diya being paid. Retaliation's an option, as well, but this lets things end; much of the fighting in Iraq was because diya wasn't possible or young males' honor required retaliation. But if the killer dies from a rockfall before he can be executed by the murdered kin's go'el (back to OT, not Arab cultures), then economic and social justice was served. We translate go'el 'avenger of blood' in some contexts; in other cases, we translate it "redeemer." Messianic groups refer to Jesus as go'aleinu, 'our avenger of blood' or 'our redeemer', because he takes the fall for Xians. The lamb at passover was to avert that fate, since the firstborn male would bear the sins of those he was responsible for, having a double portion of any inheritance (in Hebrew law). The English translators gutted much of the meaning by assuming there could be no link between the OT and the NT folk, however obvious the connections.
In another sense, it made every life matter, not just that of the group. The group would enforce justice, esp. for the weak (ideally, not that this happened most of the time). Every life was holy and to be respected and deserved to have the rules implemented fairly (which meant 'unbiased'--the writer that you shouldn't favor the wealthy at trial because of his wealth and importance also wrote that you shouldn't favor the poor because of his poverty). At the same time, there were some harsh penalties for doing things that lead to people being wrongfully convicted in the US. If you lied at trial to convict the wrong person, you were subject to the same penalty the person got. If you lied to sentence a man to death and it was found out after he was killed that the wrong person was killed, you've asked for the death penalty. (Errors happen; this is intentional.) This was complicated when there was no strong, central authority exerting strong control over everywhere. In other words, the usual state of affairs.
The legal system as set up wasn't an individual owing allegiance to the all-important group. If an individual did something wrong, there was no jail where the individual, having raped a woman or stolen an ox or defrauded a widow owed "his debt" to everybody else and paid "society". He owed his debt to the person he wronged (and to God, presumably). He made good by doing what was necessary, having his face rubbed in the wrong he'd done until he'd expiated the wrong by making compensation, if that was possible. There was no "40-year to life" cruelty and no mechanism for it. As I said, in our system it's deemed more just to lock up a person so that he exits with nothing at retirement age, often in poor health, and lives in destitution for what remains in his wreck of a life. Of course, secular thought has room for the idea that death may be better (unless it's euthanasia, which is also staging a come-back in popular, secular thought, but this gets back to a utilitarian argument, not one based in any sort of traditional morality) and, in the end, for many cultures, even death isn't a real hurdle when it comes to justice.
= new reply since forum marked as read
Overall, though, I think Christianity learned a lot from the Romans when they took over that civilization. Nobody did retribution like the Romans did. They were known to depopulate entire regions for some slight to the Empire. Some of the most vicious wars in European history involved one Christian sect fighting another.
