How have great intellectuals been able to adhere to the ideologies of a totalitarians regimes?

Whether it's communism, nazism etc. For example for France I am thinking of Jean-Paul Sartre who was a communist.

But I find it amazing how bright minds are able to adhere to this
How have great intellectuals been able to adhere to the ideologies of a totalitarians regimes?
How have great intellectuals been able to adhere to the ideologies of a totalitarians regimes?
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