The most pernicious ideology of the last sixty years was George Sorel's syndicalism and his enthusiasm for the action directe. Generated by a frustrated French intellectual, it soon captivated the literati of all European countries. It was a major factor in the radicalization of all subversive movements. It influenced French royalism, militarism and anti-Semitism. It played an important role in the evolution of Russian Bolshevism, Italian Fascism and the German youth movement which finally resulted in the development of Nazism. It transformed political parties intent upon winning through electoral campaigns into factions which relied upon the organization of armed bands. It brought into discredit representative government and "bourgeois security," and preached the gospel both of civil and of foreign war. Its main slogan was: violence and again violence. The present state of European affairs is to a great extent an outcome of the prevalence of Sorel's teachings.
The intellectuals were the first to hail the ideas of Sorel; they made them popular. But the tenor of Sorelism was obviously anti-intellectual. He was opposed to cool reasoning and sober deliberation. What counts for Sorel is solely the deed, viz., the act of violence for the sake of violence. Fight for a myth whatever this myth may mean, was his advice. "If you place yourself on this ground of myths, you are proof against any kind of critical refutation." What a marvelous philosophy, to destroy for the sake of destruction! Do not talk, do not reason, kill! Sorel rejects the "intellectual effort" even of the literary champions of revolution. The essential aim of the myth is "to prepare people to fight for the destruction of what exists."According to the Wikipedia article on him,
Sorel denounced the war and in 1917 praised the Russian Revolution, which was later printed in an official Soviet Union publication, Russian Soviet Government Bureau, calling Lenin "the greatest theoretician of socialism since Marx and a statesman whose genius recalls that of Peter the Great.” He wrote numerous small pieces for Italian newspapers defending the Bolsheviks. Less than one year later in March 1921, Sorel turned his praise towards a rising Fascist leader in Italy, writing that “Mussolini is a man no less extraordinary than Lenin. He, too, is a political genius, of a greater reach than all the statesmen of the day, with the only exception of Lenin…”
Zeev Sternhell mentions frequently Sorel  as one of the men who led the way to the fusion of the left-wing revisionists and of the right-wing ultranationalists into what later became fascism....Thus, the workers must return to strikes and violence as their main political tool, so Sorel says. This gives the workers a sense of unity, a return to dignity, and weakens the dangerous and mediocre middle-class in their struggle for power, and their attack on capitalism.