The relation between philosophy and dictatorships is that there have been several large atrocious dictatorships in the 20th C, next to quite a few equally atrocious smaller ones, all of which were claimed to be the result of specific philosophies and and specific philosophers from the 19th C: Fascism and National Socialism were much inspired by Nietzsche, and Communism by Marx.  See Ordinary men - and it is a moot question how much in communism and national socialism is due to the ideas of Marx resp. Nietzsche, and how much is due to the apparently innate totalitarian nature of ordinary men, who are not capable of generating their own philosophies but have turned out to be quite willing executioners of dictators, often from deep and sincere feelings of loyalty to the Party or the Fatherland.