[placeybordeaux]

The purpose of prisons isn't well agreed upon. It could be for keeping the population safe from people that would do them harm. It could be to punish those who do harm because those who do bad things deserve to be punish. It could be make everyone believe they will be punished if they do something wrong and therefore deter bad behavior. It could be to control someone enough to rehabilitate them.

There's probably others. Not everyone agrees on which one the US judicial system obeys.