How about a Confederate States of America Civ?

[Dauphin]

That description makes me thing of pre-1917 Russia.

Interesting alternate history - the USA consisting of the current US less the Southern States, the CSA consisting of the Southern States and Central America, and Canada allied with the US. Now what if the southern aristocracy were overthrown and replaced by a Communist regime.

What an intriguing WWII scenario we have.:

European scenario as before, Pacific scenario as before, but the whole of N.America in a similar position to Europe - i.e at the brink of war - and assume in the civ scenario that the CSA declares war if the US or Russia join the war.

[Tingkai]

If you do create a CSA, it should have an extra worker at the beginning, but belongs to another AI civ.

The cities should have a higher propensity to revolt, reflecting the need to keep troops in cities to control the slave population.

The CSA should have reduced democracy benefits.