Ah yes, the Star Trek episode where a planet had a government resembling Nazi Germany. And the leader there was a figurehead who had to be doped up to give speeches as I recall. The real powerful man was behind the scenes, who used this figurehead leader as a puppet.
“Patterns Of Force’’.
Correct, the episode was ‘Patterns of Force’. John Gill was a cultural historian observing the planet Ekos, which was in a state of anarchy. He figured that the Ekosians needed a good case of Nazi Socialism to get them in line, and became a doped-up puppet for the regime that came to power.