Great question. Here are my answers:

1. Protect society by preventing and deterring crime, both in the specific case of the person being prosecuted and others.

2. Preventing crime includes doing so by preventing bad actors from being around other people who they could kill or maim or whatever other bad thing they like to do.

3. When possible, make victims whole.

4. I don't believe in punishment as valid, but making victims happier has substantial value. So from a societal point of view, I want punishment to have a specific purpose; part of that purpose may be giving victims a sense of justice.

5. "Ensuring laws are implemented," strikes me as a second-order question; we want laws to be implemented fairly and equitably to achieve the above goals. Uniform sentencing for similarly-situated bad actors is something that accomplishes crime prevention.

6. Make more total utilons for society.

(I'm a prosecutor; that doesn't mean I'm right about any of this.)