NancyLebovitz:

In some ways, things have gotten better, not worse. Both communism and Nazism claimed scientific backing. I don't see anything like that on the horizon.

These political systems, however, are now distant in both time and space, and their faults can be comfortably analyzed from the outside. The really important question is in what ways, and to what degree, our present body of official respectable knowledge and doctrine deviates from reality, which is far more difficult to answer with any degree of accuracy. This is both because for us it's like water for fish, and because challenging it is apt to provoke accusations of crackpottery (and perhaps even extremism), with all their status-lowering implications.