The late political philosopher Eric Voegelin (1901–1985) used to caution his students always to look for the forbidden question (die verbotene Frage) when analyzing the anti-rational ideologue. Voegelin devoted a very nice little book to the subject, Science, Politics, and Gnosticism, in which he thoroughly exposed Marx as an "intellectual swindler."  Well, Marx is dead, but Marxism is not....

At the very birth of rational discussion, Socrates learned all about lying, power-hungry politicians by asking them innocent questions. But his innocent questions were forbidden questions, in the view of the immoral Athenians to whom Socrates addressed them. When he refused to relent, the great politicians of Athens put Socrates on trial. The compliant court condemned him, and ordered him to take the Hemlock. 
Now that’s poisonous.