Christianity? That is a stretch. Christians believe in divine forgiveness and some sects even believe man does not have the right to punish man; that doing so is doing God's job.

Punishment as retribution is way, way older than Christianity.

Are we hanging onto it in the United States as a relic of our (specifically) Puritan origins? Possibly.

> Perhaps it's a reflection of Christianity.

It's a reflection of Puritanism, not Christianity as a whole.

What I meant is that it could be a manifestation of an archetype in the Christian imagination - the 5th circle of hell. I did not have any conscious implementation of a doctrine for dealing with punishment in mind.