“Political liberalism in its late period with its concept of freedom of opinion, which in any case possesses a certain affinity to relativism, insofar as everyone is to be allowed to think what he wishes, because they are only thinking what is most favorable to their interest and self assertion, regardless of its truth–this liberalism was by no means secure against such perversions of the concept of ideology. And this proves once again that totalitarian rule was not imposed on mankind from without by a few desperados, that it was by no means a traffic accident on the superhighway of progress, but that there were the destructive forces in the midst of our culture which were growing to ripeness.”
Pp. 194–195 in Frankfurt Institute for Social Research. 1973. Aspects of Sociology. Translated by J. Viertel. Boston: Beacon Press.