Charisma and the failure of fascist regimes to survive the death of The Leader
By 
From Robert Paxton’s The Anatomy of Fascism (2004):
[Fascist leadership] rested on charisma, a mysterious direct communication with the Volk or razza that needs no mediation by priests or party chieftains. Their charisma resembled media-era celebrity “stardom,” raised to a higher power by its say over war and death. It rested on a claim to a unique and mystical status as the incarnation of the people’s will and the bearer of the people’s destiny. A whiff of charisma is not unknown among traditional dictators, of course, and even some democratically elected leaders, such as Churchill, de Gaulle, and the two Roosevelts, had it. Stalin surely had charisma, as the public hysteria at his funeral showed. But Stalin shared his role as the bearer of historical destiny with the Communist Party, which made succession possible even if palace intrigues and murders multiplied before the successor could emerge. But fascist rule is more nakedly dependent on charisma than any other kind, which may help explain why no fascist regime has so far managed to pass power to a successor. Both Hitler and Mussolini had charisma, though Mussolini’s declining vitality in middle age and his tawdry end made most people forget the magnetism he had once exerted, even outside Italy.
Charisma helps us understand several curious features of fascist leadership. The notorious indolence of Hitler, far from making Nazism more tepid, freed his subordinates to compete in driving the regime toward ever more extreme radicalization. A charismatic leader is also immune from the surprisingly widespread grumbling against the administration that quickly arose in both Germany and Italy. At the same time, charismatic leadership is brittle. It promises to the Volk or the razza, as Adrian Lyttelton once noted, “a privileged relation with history.” Having raised expectations so high, a fascist leader unable to deliver the promised triumphs risks losing his magic even faster than an elected president or prime minister, of whom less is expected. Mussolini discovered this rule to his sorrow in July 1943.
See also cumulative radicalization and the contemporary Republican party.