Ever watched Psycho-Pass? Great anime. Setting is a sort of an AI coordinated Panopticon in which the Psycho-Pass system equips it's enforcers with firearms capable of either paralyzing a "reformable" latent criminal, (namely someone with a psycho-pass measured to be >100, but <300, or eradicate the irredeemable (score >300). The series focuses around the dilemmas created by instilling in this system the sole monopoly on violence, and this magical firearm and Psycho-pass computing device. There is a poignant point made of the weapons design. In spite of the Psycho-Pass systems assumed infallibility, each weapon is equipped with a trigger, that must be pulled to fire it. The system itself is not given final say on whether to do so. It is left as a matter of the Enforcer's discretion.
Much the same dynamic can be inferred to be taking place with the U.S. legal system. The weapon and it's wielder is analogous to the judges; the Psycho-pass system to juries. The interesting consequence here with this analogy is that the wielders of these weapons for the Psycho-pass system are almost entirely latent criminals according to the judgement of the Psycho-Pass system itself.
Point being, the U.S. addresses things through common law with an adversarial criminal law system. The judge has a great deal of discretion to bring to bear on the cases they decide. There is as much, if not more controversy to be found when statutory punishment overrides any possibility of a judge applying discretion, leaving only executive clemency as a safety hatch.
Legal systems are not intended to be suicide pacts. Rather a collective effort of trying to seek the thing most resembling justice; a thing that is only measurable through the collective action of humanity, and which when responsibility for this measurement is delegated to fewer and fewer people, tends to morph away from what the entirety of us would probably converge upon being just. The arguments you're having with others highlights this very dynamic very strongly to me. Since it is difficult for a single party to manifest a full 360 perspective on the aspects of moral injury as endemic to the practice of justice, and the condition of injustice. Pragmatism, alas, is a bit of a bitch like that.