Star Trek Cold War analogy:
Federation = NATO. Group of freedom loving planets (countries) with the Earth (USA) as the superpower.
Klingons = Russians/Soviets. Dictatorship with emphasis on military spending, spartan quality of life. Guttural language.
Vulcans = Japanese. Logical, emotionally reserved, black hair, asiatic complexion -- pointy ears instead of slanted eyes. Previously warlike and violent, but recently found their role as peace-loving non-combatants with a defense force but never or rarely involved in any galactic battles.
Romulans = Chinese and/or North Koreans. Rarely seen, no real diplomatic ties. Referred to as distant "cousins" to the Vulcans. Neutral zone = Korean DMZ.
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The Klingons and Romulans serving as proxies for the Soviets and Communist Chinese.
Many compare the Cardassians to the Nazis and I think there's some truth there but again looking at the world in the early 90s when they were created and they are even more like South American and Iberian military dictatorships of the 70s and 80s; most clearly Argentina or Chile.
Finally the Bajorans are a clever if not controversial mix of Israeli and Palestinian with a touch of Irish Republican. This of course gives the Cardassians a role in which they serve as the British and/or Israelis.