Regarding the debate on trying 12 year olds as adults, I was reminded of this case (about which there's a very creepy Peter Jackson movie). The essence of it is that two fourteen year old girls who had a deeply obsessive friendship with each other conspired to murder the mother of one of them and did actually violently bludgeon her to death. They were charged, tried, and saved from the death penalty by their youth...and released when they were adults. Both repented of their crime, and grew up to be productive members of society. (One is actually a famous mystery novelist.) 

Is this a desirable outcome? If there's a chance of rehabilitating someone, should that be a goal, or not? 

Outside the case of children who commit crimes, what about adults? After they've served their sentences (be that 5 or 10 or 30 years), what should happen? Is it important to make sure they can re-enter society (with support/job training/etc), or should they be permanently consigned to the margins?