While repealing laws and police reforms are important in alleviating mass incarceration, the problem is likely to continue as long as prosecutors are permitted to operate with so few constraints.
Private prisons are private in name only. They are merely adjuncts of the state, and the real problem is these prisons warehouse many people the state should not have put in prison in the first place.
Federal judges have served as loyal foot soldiers for police who enthusiastically use every trick in the book to violate and nullify the Bill of Rights.
Qualified immunity is the clearest example that the rule of law is dead (or, perhaps, never existed); government officials live by one set of rules, and the rest of us live by another.