The typical usage of the lex talionis, the law of tit for tat, “an eye for an eye, a tooth for a tooth” (Exodus 21:23–27) is that you should take an eye to repay the loss of an eye, which is actually a disputed reading.

Some people think that chapter is about the limits of punishment, for example that the loss of an eye should not be punished by death. In short: there is no interest on injuries. The verse, under that reading, doesn’t require a minimum punishment, it just establishes a maximum. In this case the snippet permits lethal retribution but doesn’t require it.

What you want to be quoting is Exodus 21:12 — just below the bit about how to sell your daughter as a slave — “Whoever strikes a man a mortal blow must be put to death.”

That said:

One false positive execution is too high a cost, and the justice system can’t guarantee against false positives (nor do we really expect it to).

Plus:

There’s evidence that capital punishment increases incidence of violent crime by socializing people to see violence as a valid way of solving problems. People think by analogy, and our social institutions are didactic.

State-sponsored execution costs more, has troubling moral implications, adds nightmare scenarios to our justice system, and makes society more violent.

So yeah: No point in discussing it really, it’s just a bad idea. I mean, what’s next? Weighing the pros and cons of indentured servitude for sub-prime mortgage defaulters? Debtors’ prisons? This is the 21st century, not the 19th.

There’s some evidence that executions are more expensive than life imprisonments in the US.

I often wonder if people are really for the death penalty or just frustrated that life in prison often doesn’t result in life in prison. Victim’s families have to keep track of the murder and make sure they don’t miss the parole trials to keep the murder in jail. (thinking about manson here) If I had to be connected to the murderer for the rest of the murderer’s life, especially if he killed my child, I would certainly be wishing for his death.

Gimme a break.

And seeing as his counter-arguments consist of “I don’t know how psychologists work, so they must be lying if they say they know more about psychology than me” and quoting a romantic comedy from 1969, I remain unconvinced.