Originally Posted by u-Bob

The entire original concept of laws is not about the most efficient way to organize things, but to prevent (and repair) injustice. Murder is an act of injustice, theft is an act of injustice, rape is an act of injustice etc. All those things are 'mala in se'. Merely talking or fantasizing about committing murder or about pulling off a heist or about rape is not an act of injustice. Locking people up when they have not committed an act of injustice but when some psychiatrist believes they might some day commit an act of injustice is an act of injustice in itself.