For those not in the know, this was the infamous "Planet of Nazis" episode where a professor decided that fascism was the best system if it was run better so he went to a primative planet and got all the people to embrace Naziism with him as the leader, until his deputy decided that he wanted to be in charge so he used drugs to basically lobotomize the professor and propped him up in a chair behind some microphones and had a voice double make speeches that were overdubbed, making him a mindless puppet that was only seen in a totally controlled manner.
Man, Star Trek nailed this one in every way.