Generally, public opinion is strong for justice, although some want only vengeance – "an eye for an eye, a tooth for a tooth”.
The other extreme rejects this and sees imprisonment primarily as an attempt to rehabilitate the criminal.
The traditional Christian teaching is a bit more complicated. Those who believe in God the Creator accept that serious evil disturbs and distorts nature’s proper order.
Punishment is designed to redress this disorder and when the offender voluntarily accepts his punishment this enhances the return to equilibrium.
Punishment should be medicinal, contributing tothe personal reform of the offender.
I should pray for Saddam’s soul but cannot weep for him. I weep rather for his many victims.