The Lunar United Kingdom was founded when the Soviets and the US felt things could go out of control if they had too large of a border. The two nations had a contest until a coalition of ousted monarchs came up with a plan. Their plan was accepted under the condition there would have to be at least 1/16th of the Senate filled with Communists.
The LUK has many Kingdoms each serving as a state or a province. The Kingdoms all swore alligeance to the High King, a rotating position between all the Kings.