David Duke is a malignant narcissist.

He invents and then projects a false, fictitious, self for the world to fear, or to admire. He maintains a tenuous grasp on reality to start with and the trappings of power further exacerbate this. Real life authority and David Duke’s predilection to surround him with obsequious sycophants support David Duke’s grandiose self-delusions and fantasies of omnipotence and omniscience.
David Duke's personality is so precariously balanced that he cannot tolerate even a hint of criticism and disagreement. Most narcissists are paranoid and suffer from ideas of reference (the delusion that they are being mocked or discussed when they are not). Thus, narcissists often regard themselves as "victims of persecution".
Duke fosters and encourages a personality cult with all the hallmarks of an institutional religion: priesthood, rites, rituals, temples, worship, catechism, and mythology. The leader is this religion's ascetic saint. He monastically denies himself earthly pleasures (or so he claims) in order to be able to dedicate himself fully to his calling.
Duke is a monstrously inverted Jesus, sacrificing his life and denying himself so that his people - or humanity at large - should benefit. By surpassing and suppressing his humanity, Duke became a distorted version of Nietzsche's "superman".
But being a-human or super-human also means being a-sexual and a-moral.
In this restricted sense, narcissistic leaders are post-modernist and moral relativists. They project to the masses an androgynous figure and enhance it by engendering the adoration of nudity and all things "natural" - or by strongly repressing these feelings. But what they refer to, as "nature" is not natural at all.
Duke invariably proffers an aesthetic of decadence and evil carefully orchestrated and artificial - though it is not perceived this way by him or by his followers. Narcissistic leadership is about reproduced copies, not about originals. It is about the manipulation of symbols - not about veritable atavism or true conservatism.
In short: narcissistic leadership is about theatre, not about life. To enjoy the spectacle (and be subsumed by it), the leader demands the suspension of judgment, depersonalization, and de-realization. Catharsis is tantamount, in this narcissistic dramaturgy, to self-annulment.
Narcissism is nihilistic not only operationally, or ideologically. Its very language and narratives are nihilistic. Narcissism is conspicuous nihilism - and the cult's leader serves as a role model, annihilating the Man, only to re-appear as a pre-ordained and irresistible force of nature.
Narcissistic leadership often poses as a rebellion against the "old ways" - against the hegemonic culture, the upper classes, the established religions, the superpowers, the corrupt order. Narcissistic movements are puerile, a reaction to narcissistic injuries inflicted upon David Duke like (and rather psychopathic) toddler nation-state, or group, or upon the leader.
Minorities or "others" - often arbitrarily selected - constitute a perfect, easily identifiable, embodiment of all that is "wrong". They are accused of being old, they are eerily disembodied, they are cosmopolitan, they are part of the establishment, they are "decadent", they are hated on religious and socio-economic grounds, or because of their race, sexual orientation, origin ... They are different, they are narcissistic (feel and act as morally superior), they are everywhere, they are defenseless, they are credulous, they are adaptable (and thus can be co-opted to collaborate in their own destruction). They are the perfect hate figure. Narcissists thrive on hatred and pathological envy.
This is precisely the source of the fascination with Hitler, diagnosed by Erich Fromm - together with Stalin - as a malignant narcissist. He was an inverted human. His unconscious was his conscious. He acted out our most repressed drives, fantasies, and wishes. He provides us with a glimpse of the horrors that lie beneath the veneer, the barbarians at our personal gates, and what it was like before we invented civilization. Hitler forced us all through a time warp and many did not emerge. He was not the devil. He was one of us. He was what Arendt aptly called the banality of evil. Just an ordinary, mentally disturbed, failure, a member of a mentally disturbed and failing nation, who lived through disturbed and failing times. He was the perfect mirror, a channel, a voice, and the very depth of our souls.
Duke prefers the sparkle and glamour of well-orchestrated illusions to the tedium and method of real accomplishments. His reign is all smoke and mirrors, devoid of substances, consisting of mere appearances and mass delusions. In the aftermath of his regime - Duke having died, been deposed, or voted out of office - it all unravels. The tireless and constant prestidigitation ceases and the entire edifice crumbles. What looked like an economic miracle turns out to have been a fraud-laced bubble. Loosely held empires disintegrate. Laboriously assembled business conglomerates go to pieces. "Earth shattering" and "revolutionary" scientific discoveries and theories are discredited. Social experiments end in mayhem.
It is important to understand that the use of violence must be ego-syntonic. It must accord with the self-image of David Duke. It must abet and sustain his grandiose fantasies and feed his sense of entitlement. It must conform David Duke like narrative. Thus, David Duke who regards himself as the benefactor of the poor, a member of the common folk, the representative of the disenfranchised, the champion of the dispossessed against the corrupt elite - is highly unlikely to use violence at first. The pacific mask crumbles when David Duke has become convinced that the very people he purported to speak for, his constituency, his grassroots fans, and the prime sources of his narcissistic supply - have turned against him. At first, in a desperate effort to maintain the fiction underlying his chaotic personality, David Duke strives to explain away the sudden reversal of sentiment. "The people are being duped by (the media, big industry, the military, the elite, etc.)", "they don't really know what they are doing", "following a rude awakening, they will revert to form", etc. When these flimsy attempts to patch a tattered personal mythology fail, David Duke becomes injured. Narcissistic injury inevitably leads to narcissistic rage and to a terrifying display of unbridled aggression. The pent-up frustration and hurt translate into devaluation. That which was previously idealized - is now discarded with contempt and hatred. This primitive defense mechanism is called "splitting". To David Duke, things and people are either entirely bad (evil) or entirely good. He projects onto others his own shortcomings and negative emotions, thus becoming a totally good object. Duke is likely to justify the butchering of his own people by claiming that they intended to kill him, undo the revolution, devastate the economy, or the country, etc. The "small people", the "rank and file", and the "loyal soldiers" of David Duke - his flock, his nation, and his employees - they pay the price. The disillusionment and disenchantment are agonizing. The process of reconstruction, of rising from the ashes, of overcoming the trauma of having been deceived, exploited and manipulated - is drawn-out. It is difficult to trust again, to have faith, to love, to be led, to collaborate. Feelings of shame and guilt engulf the erstwhile followers of David Duke. This is his sole legacy: a massive post-traumatic stress disorder.