* Asset forfeiture, at least in its current widespread form that now includes whole departments and is assumed to be a regular part of the budget.
* It used to be a scandal in all but the worst cities if an officer killed an unarmed suspect, that at least warranted an investigation or trial, instead of the current norm of rewarding murder with a paid vacation.
* Even in a country stereotypically known to love firearms, we used to limit regular police work to the same type of small arms that the average citizen might own. More powerful weapons were limited to special-purpose groups. Now, police = without adequate training - get to play soldier with APCs, camo (!), and a variety of modern weapons that are overpowered or unsuited for police work.
* A gang-mentality that has been growing for a long time. There used to be some truth to the idea of a police department having "a few bad apples" among many generally decent officers. Now we have a situation where former officers have spoken about how they had to resign (some voluntarily, some force out) because they didn't want to aid and abet the crimes of other officers.
[1] the problem was big enough that significant parts of the Constitution attempt to limit corruption and its effects
That profession has always attracted those who will abuse the rights of others and seek power for personal gain, however, that's an intrinsically human quality that applies in many contexts. What is clear is that its more damaging in some than others, and its momentum/inertia is relevant. Pass a certain threshold of such behavior and, as per game theory, the motivations of the entire network (or "culture") change.
We're hearing about it more, but I'm also gravely concerned about the rapid rise in annual cumulative seizures. We may never solve the intrinsic problem, but if we don't take action now things could quickly become untenable with no method of recourse.