[netcan]

China's ethnic groups are small, weak and concentrated in remote areas. They really are probably not a political factor. I really can't see this ever being the dividing line of a civil war. They might demand autonomy or independence but that's not really a civil war.

Any serious civil strife that could effect the political direction of the country is most likely to be of the revolutionary kind. The most likely (though still not that likely) scenario I can think of is post economic downturn combined with political scandal. It would probably be a nebulous combination/coalition of demands/factions. Pick a basket of anti regime, pro peasant, anti corruption, pro democracy, human rights. Maybe Christianity or religion in general plays a role.

I think you need to draw a line though between civil strife and revolutionary agitation. I think the urban/rural divide will most likely manifest in the latter.