Assuming the CSA can win some sort of victory in the ACW I have always wondered more about the civilian side of each government and people. I wonder without the South if the USA would drift significantly to the left politically. Certainly in the 1920s-30s the more industrial north would have a higher percentage of left leaning pols than the South. Turtledove seems to accept this in his ACW alt series with the Democrats and Socialist swapping power. But I don't think his socialist are anywhere near radical enough.
Even a moderate socialist government in the USA would have dramatic impacts in economics (like earlier versions of Norris-LaGuarda Act, NLRA, Unemployment Insurance, Min Wage, etc). Tax rates would probably be relatively higher in the North, but the social savings might off set this and certainly a tariff would protect Northern Industry.
Education would be different. The South had bitterly opposed public education and was very slow to expand the system. This would create an academic split. To give one example the North would likely have a far more extensive systems of 'land grant' colleges, where the South would probably only have a smattering of elite private schools, and a few public institutions.
Culturally you would have a wide difference too. Without the great black migrations you would only have a few enclaves of blacks in the North. Perhaps more immigrant cultural influence? An earlier inclusion of Yiddish, Southern European or Slavic trends?
Jay