idiotas úteis

Nada como voltar aos clássicos — Planned Chaos (PDF) (Ludwig von Mises, Socialism: An Economical and Sociological Analysis, 1951):

Marx and the Marxians erred lamentably when they assumed that the masses long for a revolutionary overthrow of the "bourgeois" order of society. The militant communists are to be found only in the ranks of those who make a living from their communism or expect that a revolution would further their personal ambitions. The subversive activities of these professional plotters are dangerous precisely on account of the naivety of those who are merely flirting with the revolutionary idea. Those confused and misguided sympathizers who call themselves "liberals" and whom the communists call "useful innocents," the fellow-travellers and even the majority of the officially registered party members, would be terribly frightened if they were to discover one day that their chiefs mean business when preaching sedition. But then it may be too late to avert disaster.

Entre a caracterização caridosa de Mises ("useful innocents") e a de Bezmenov (2'24") fica a de "idiota útil", que é a mais utilizada comummente.