Roman Empire: History teaches that the Roman Republic devolved into psychopathic dictatorial empire; characterized by oligarchic families competing among themselves for power and wealth within vicious inner-circles.
This occurred while proclaiming to the public that their government still upheld the highest ideals of their Republic, and proclaiming expanding empire was only and always in "self-defense."
Emperor Domitian's assassination in 96 AD (among ~22 murdered emperors), allowed historian Tacitus to write The Agricola, a biographical text of his father-in-law contrasting claimed virtue of Roman military and citizenry with the emperor's utterly corrupt despotism.
Importantly, this text describes the problem of virtuous Romans within a psychopathic government, with responses between extremes of martyrdom to sycophantic servility. Tacitus describes Agricola attempting to uphold virtue; but without recognition of any evil in serving an expanding dictatorial empire. Tacitus seems to assume the ideal of mos maiorum, "custom/virtue of Roman forefathers" will eventually triumph over the evil of present "leadership."