Demographic Bases For Partitions Of Vietnam/Korea?

What characteristics (if any) of the population/geography/economy of the northern and southern regions of Vietnam and Korea led to the respective northern parts being (at the respective periods of time) communist and the southern parts being anti-communist? I suppose proximity to/influence from China/Russia may have had some geopolitical influence. But what other features of the population (e.g., any differing ethnic/tribal/linguistic affiliations in the different regions, religious differences, agrarian v. industrial economic bases, traditional north/south rivalries) led to the dramatically different political regimes set up in the respective regions?

It was geographic, not demographic.

None. Absolutely none. They were purely arbitrary divisions between the Soviet Union and the rest of the Allies.

Well – but wasn’t S. V.N. (or some provinces thereof), say, more Catholic than the North? Maybe that didn’t matter; and certainly the V.C. seemed to have some support in most regions.

While I (evidently) don’t have any cite for my suspicion that there might be more to it than the respective regions being hapless pawns of the respective Great Powers, recent troubles in Africa (for instance) have made me curious about explanations for regional conflict beyond “imperial proxy power struggle” or “senseless suicidal civil war” – I was certainly not fully aware before of the extent of tribal/societal distinctions that, it now appears, drive a lot of the African conflicts, as we’ve been conditioned to view everything in terms of imperialism, First v. Third World, Caucasian v. black, etc.

[slight hijack of own thread]For an argument as to why civil wars are not always “senseless” from the perspective of participants, see
http://www.exile.ru/172/172120000.html
[/slight hijack of own thread]

From what I recall, very many of the Catholics from North Vietnam migrated to South Vietnam quite soon after the partition.