“Ideology” is a word with a number of meanings, but the most useful, I think, was put forward by Eric Voegelin. In his thought, “ideology” signifies the attempt to create an abstract “second reality” that somehow seems preferable to the real world for the ideologue. The ideologue then attempts to live in that constructed reality, and to force others to do so as well.
The attempt will, of course, fail, since we can only live in the real world. But that does not mean that a lot of damage won’t be done along the way. Let us begin by looking at a case (mostly) from the past, to gain a clearer picture of this conception of ideology apart from current concerns.