Yeah, a state department side-steps a lot of those problems (but also possibly lets states ignore it). A federal law requiring police interactions to be record

Yeah, a state department side-steps a lot of those problems (but also possibly lets states ignore it). A federal law requiring police interactions to be recorded and submitted to a state entity and requiring it be stored for a certain period would probably suffice. Then the FBI or whoever investigated an issue Federally (if it got to that) could subpoena it, since it's supposed to exist, and be handled by the state. I agree it should be a black box. Rule #1 for accountability is that you don't rely on the entity that's being examined to give absolutely correct info. Whether that's debugging a process or reviewing an organization, outside instrumentation is essential.