Malgus, I know that the system gives them to much power and many use that power for the wrong reasons.
Man will always have this problem, some start being good and end up being bad. This is why no matter what system of screening they develop there will always be some bad. Money, power are two of the reasons this happens and not just with the police. It happens to all. God knows this well.
I do think that the system need a new screening system. Every 4 to 5 years they should be looked at by an independent group to make sure that they have not lost they way.