According to some scholarly articles, discretion is exactly how rouge states make almost everything illegal then allow the police to victimise minorities, legally. Very sketchy idea, maybe just make BAD things illegal and arrest/prosecute everyone and anyone, which would reduce the opportunity for them and the law to manipulated by bad politicians.

Deadly Discretion: The Failure of Police Use of Force Policies to Meet Fundamental International Human Rights Law and Standards

Link: https://lawreviewblog.uchicago.e

The University of Chicago Law School's International Human Rights Clinic unveils a groundbreaking study on police use of force.