The theme is centralized control of the lives of human beings by an authority that will stand for no opposition or recourse.

Marxism has simply been the most globally and influential widespread example of this over the past century. Its appeal is still strong in the Third World, or even in more advanced nations like Venezuela.

Obviously, it hasn't been the only major example of totalitarianism during that time, but as I have pointed out in the past, it is still easy to find people who sympathize or directly support Marxism and its principles, even people in positions of authority or in academia. This is not true of other famous totalitarian regimes.

You don't find professors with pictures of Hitler on their walls, or kids wearing Himmler T-shirts. I've seen kids at our high school with Che and even hammer-and-sickle T-shirts (the latter seemed to be part of some senior group thing). Odds are they have no idea what it means, but their teachers should.