stare decisis, trials have witnesses in the USA

sta·re de·ci·sis /ˌsterē dəˈsīsəs/

noun LAW

the legal principle of determining points in litigation according to precedent.  
____________

extortion becomes precedent
selling favors to mobsters and oligarchs becomes precedent
bribery becomes a permissible precedent
immunity from prosecution becomes precedent
intimidation and hate speech becomes precedent.