of course there are common threads between so-called 'left' and 'right' wing extremisms... authoritarianism or revolution, with whatever ideology, can all too easily morph into totalitarianism, and co-opt whichever set of ideas works best whether fascist, communist, Jacobin, or Muslim.

Anyone here read Michael Ledeen's "The First Duce: Gabriel D'Annunzio and the Free Republic of Fiume [1919]"?  I think it's a must read for anyone interested in the intersection of radicalism and personality.  A great deal of what later became standard political tools for everyone from democrats to nazis and communists was invented by D'Annunzio, in one of the most bizarre revolutionary proto-states ever created.  It was anarcho-syndicalist, radically egalitarian with an unbelievably ahead-of-its-time ideology of freedom for all colonized peoples, rejected alliance with either communists or mussolini, and much more besides... the founding principle of the 'republic' was music, and every night they had opera and fireworks...