Here is an interesting article by John Derbyshire: "Isms and Wasms: The pros and cons of ideology." According to the author's understanding, an ideology divides the world into two camps, one of which is the repository of all good and the other the locus of all, well, evil. Those in the "opposing" camp are considered beyond the pale and are treated as such, sometimes at the cost of millions of lives.
The age of isms did not end with the Cold War. Nationalism aside, plenty of other isms refused to become wasms in 1989, and a few new isms have sprung up. There are still ideologues among us, and I believe there always will be. The ideologue is a standard human type, found in all times and places. His style of thinking is one of the ways human beings have devised for making sense of the world. I think we are all capable of ideological thinking in some degree; in that sense, the pure ideologue — the "ist" behind the "ism" — is just displaying a common human tendency in hypertrophied form.
Yet Derbyshire admits that ideologies have often originated much that is good. This is what I would call the moment of truth in these ideologies. For example:
The great — and, to my mind, wonderful — improvements in the lives of working-class people that came about in the middle 20th century were driven partly by Marxist and Leninist ideologues, who would have murdered the bourgeoisie en masse if given the opportunity. . . . Similarly, the U.S. civil-rights movement of the 1960s included in its ranks some people who were, or soon became, white-hating racist ideologues; but I'm still glad we got rid of Jim Crow. . . . Once an ism has served its historical purpose, however, I'd like to see it become a wasm as speedily as possible. The fact that this hardly ever happens is, it seems to me, the source of many of the world's ills and annoyances.