I don’t think I disagree with you in any way, and you make excellent points, but it seems to me that if police unions wield too much power, it’s because someone wants them to have that power. The thin blue line works because (apparently) no one who can challenge police silence is doing so. Now that we have citizen videos and (occasionally) police body cameras, the lies that abusive policemen tell can be overcome.

I don’t want to sound too tin-hatty, but someone other than individual rank-and-file policemen is benefiting economically from brutality. I don’t know who it is, but when you have systemic imbalances of power, the people in power often do whatever it takes to maintain their advantage.