I always felt Star Trek politics were pretty cut and dried, as each race either directly represented a specific country or ideology
Federation: Western world, especially the US, given the diversity of participants.
Romulan Empire: Soviet Union, semi paranoid society, fairly closed, state security is fairly powerful and ever present (Tal Shiar = KGB). Mix of military power and secrecy to further their agenda (The plot line of supplying weapons to the Duras is straight out of the Soviet playbook of arming allies with Soviet weapons, AK-47's being the most common).
Cardassian Empire: East Germany. Odo is quoted as saying "Not even the Tal Shiar can match the Obsidian Order" in the episode The Wire. Poor, even more paranoid, uses miltary expansion to acquire resources. Obsidian Order = Stasi
Ferengi = Captialism/Wall St. where everything has a price.
Tholians = Japanese. Exotic technology, very advanced, but xenophobic to the extreme.
Borg = China. More intent on taking then innovating, seen as homogeneous mob. Suppresses dissent for the collective/society good.
Dominion = Middle East. Average religious fanatic = Jem Hadar (believe in a god and is willing to die for them). Vorta = Mullahs (use the belief of the founders to enforce their will). Founders = Typical Middle East dictator/monarchy, who use religion purely as an excuse to maintain control, and don't care what so ever about their people and throw them away with little regard.
Bajorans = Israel. Home occupied, people murdered, scattered to the wind. Rebuilds.
Klingon Empire = Probably West Germany, due to overarching militarism, and pride. As seen in TNG, battleground for the ideologies of Romulans and the Federation, similar to the ideological battles in Germany, symbolized by the Berlin Wall. But really any place where there was combat over the ideolgies could represent here (Vietnam, Korea)