> attempts to reduce discretion have historically resulted in malicious arbitrariness
You're 90% of the way to the answer. Take into account Hanlon's Razor and it should become clear.
Unless the people designing the law are smart enough to take into account every single edge case, we're faced with a choice between gross miscarriages of justice through inflexible laws, and gross miscarriages of justice through incompetent or corrupt judges.
We know the people designing the law aren't that smart; and even if they were, the laws are already too complicated. The only solution is to strike a balance between the two types of errors that minimizes their sum.
You're 90% of the way to the answer. Take into account Hanlon's Razor and it should become clear.
Unless the people designing the law are smart enough to take into account every single edge case, we're faced with a choice between gross miscarriages of justice through inflexible laws, and gross miscarriages of justice through incompetent or corrupt judges.
We know the people designing the law aren't that smart; and even if they were, the laws are already too complicated. The only solution is to strike a balance between the two types of errors that minimizes their sum.