I think the ambiguity with justice comes from the ambiguity of what exactly a crime is. What is or isn't a crime is largely a product of the society that defines it.
I believe we should start with a simple principle of "whatever an individual can do that does not directly or environmentally affect people who hasn't given their content can never be considered a crime". As long as this is not put among fundamental axioms of justice I can hardly recognize how any other attempts to apply logic to this area can make much sense.
