I always thought the Romulans were based on Asian countries.
Collective thinking and no independent thought.
Doesn’t the Romulan commander say “in another time, I could have called you friend” or something like that in one episode?
I’d never thought about that, but the Klingons were a stand-in for the Russians, so you could be on to something. Also, the Romulans and Vulcans had a common origin, so maybe the Vulcans were supposed to be like the Japanese and other Asians that allied with us, with the Romulans representing the Chinese and others that sided with the Russians.
Though, I think they were more political caricatures. They didn’t really try to give the alien races in TOS any kind of close resemblance to races on Earth.