“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.
In the real world, many of the material bases for human life are scarce. There is only so much prime agricultural land, there is only so much good pasturage, there are only so many navigable rivers, only so many good ocean ports, only so many trees, only so much gold and iron and aluminum and oil, and so on. Whether this is the doing of God or blind nature, it is the reality that we as humans find ourselves living in. It is mere wishful thinking to imagine that all these things exist in such abundance that everyone can have as much of all of them as he or she would desire.
It is one thing to acknowledge this fact, and still propose some scheme under which access to or possession of these scarce resources is more fairly distributed than it is at present. But rather than do that, Karl Marx devised a second reality in which this fact of the real world is imagined out of existence. (He actually despised policies, such as those of the moderate socialists, that simply attempted to give some people a fairer share.) In the dream world of the communist utopia, scarcity would be absent. (Marx did acknowledge scarcity to some extent, but only so far as it had been created, and existed in his time, due to the evil machinations of capitalists, and not as a basic fact about reality.) And by wishing this fact out of existence, Marx could simply ignore the need for coming to terms with it. He did not need to make any concrete proposals for how the ideal communist society would handle the distribution of goods, since in the imaginary world where nothing is scarce, there simply is no problem of distribution.
Now, of course, actual communists had to rule communist societies that existed in the actual world, not in the world of Marx’s imagination. And so they could not avoid dealing with the reality of scarcity. (It should surprise no realist that, in fact, the way they dealt with it was that the rulers, and a handful of star athletes, chess players, mathematicians, and scientists, got all of the best stuff, and everyone else had to scrape by with the leftovers.) But given that the rule of the communists depended upon belief in Marx’s second reality, the fact of scarcity could never be admitted. Instead, the continual failure of the communist utopia to actually emerge had to be blamed on capitalists, Kulaks, intellectuals, reactionaries, and so on… and thus these people were imprisoned and slaughtered by the millions. And while these horrors were obvious for anyone willing to look, many, many people in communist countries went along with the charade, for to dissent was to risk being labeled a “reactionary” oneself, and to experience, at best, social ostracism, or very often “re-education” or even death. But what is worse is that many in the West did so as well, where the only penalty they faced was being ridiculed for being on “the wrong side of history.”