I Suppose it Only Takes One

I have had this nagging question: in a nut shell, how can we trust the police? We have been discussing now for some time about how power comes about. My question has been if there was a revolution, per say, or a march on our Capital, what would keep the security (the ones with the power) from not joining the cause- what keeps a policeman loyal?

This article is about how the police are essentially corrupt, killing whenever they wish. I suppose it only takes one. Let's consider Olson and what we have learned. Assume that one cop ignores the rule of law and shoots, say a child rapist, and is concealed from the crime with help from his direct supervisor. This would definitely give the policeman incentives to continue taking the law into his own hands. Pretty soon, the entire force would be in a group that is able to do anything they want, seeing that they would have the greatest capacity for violence. I assume this is a way to see how the stationary bandit comes to power.

Maybe, the stationary bandit already has some power, like a supervisor, but does not have to show his force, but let those under him get away with using violence, while he lets it occur. If enough subordinates felt the supervisor would "ignore" there forceful evils, they would give the supervisor more power, creating a stationary bandit, if the supervisor asked them to do his "dirty work".

I wonder if this is consistent with what we have learned. I suggest that the stationary bandit(SB) does not use force himself, but by allowing it to happen, he becomes more powerful. I wonder, though, what would happen if the SB never showed force (i.e. killing someone) if one of the subordinates would "challenge" him with force. Or, maybe more simply, can an OZ really exist- does it take only one?