Supervisors have unions too. In some cases, they are in the same bargaining unit as the rank and file police they are supposed to supervise. So discipline against supervisors for failing to oversee the rank and file will run into the same union wall. Combine that with the blue line which none of them dare cross, and the fact that those making these reviews are from within the police as well (or their allies in the DA), and you see why discipline goes nowhere.
If you try to go higher up, you run into an even harder wall of politics. The police unions have incredible power in influencing elections of their own bosses. Our current LA County Sheriff, Alex Villanueva, for example, was elected with their support, and quickly proceeded to reinstate officers who had been removed by prior administrations for misconduct.
The only way your suggestion could work is if the power to discipline, whether rank-and-file or supervisor, is taken completely out of local hands and placed in an independent agency. I understand that is what you were doing in the US DOJ, and that is supposedly being revived under the new Administration. But federal review is sporadic, and not ongoing.
Some of us have been trying to take discipline out of local hands and place it in an independent state agency - just like lawyers are disciplined. But all we were able to do in CA was create that discretionary oversight for discipline and prosecution involving officer-involved killings. We really need to take ALL discipline out of local hands to stop these killings before they happen. But that is running into a hard wall of the political power of police PACs. I'm not giving up, just pointing out what a difficult job we have to make any real progress.
