> But if the DA and/or judge goes after the police, then the police stop cooperating with them on cases. I don't think that procedural issue is really the root

> But if the DA and/or judge goes after the police, then the police stop cooperating with them on cases. I don't think that procedural issue is really the root. Judges have wide authority to issue contempt of court charges (including for refusing to appear/testify/cooperate). Police officers are not immune to those, and could bear significant fines or imprisonment as a result. The issue underlying that solution is who enforces those charges? The police department sure isn't. I don't know if a judge could ask US marshals to effect the arrest or not. The judiciary relies on the executive branch to provide the muscle, and doesn't have any real means to enforce its own judgements.