I hope I am not necromancing this thread.
Their was a movement to create an 'African-American Nation', but it was both not popular among African Americans and those who did support it tended to be extremists.
I wouldn't say the movement was unpopular, black people in the United States have always considered themselves to be a separate nation than the white dominated society. Building a new STATE for that nation is what would have been less popular, and even then groups like the Nation of Islam and Black Panthers were popular in Black America (note: those groups advocated 'self determination for black americans' - and I cannot find the image with Black Panthers with guns and that sign - fudge)
Their's also the issue that outside the 'Black Belt' most of the South is either majority or plurality white.
Meaning this hypothetical nation would come out from either A. a communist revolution (or soviet invasion - what the people earlier posted), or B. an uprising akin to what happened in former Yugoslavia, e.g. in the 1960s black america rises up and the army fractures among racial lines and you see black militias in the south clearing out whites and vice-versa in the 'white' south - and the federal government is powerless as the other countries would lap up the hypocrisy of suppressing self-determination movements esp given the UN's 'decolonization' movements.
People here also forgot one thing. POD of the reconstruction being more thorough and longer, allowing a strong black middle class and economic self-determination making political self-determination easier. IF there's MORE black lawyers etc black america isnt as dependent on the whites, removing the economic slavery and shafting sharecroppers got.
African-American Civil Rights Movement destroyd this system in 1955-1968
But Wat If the politician push racial segregation a step further ?
White America is hypocritical and would have both A. suppressed black nationalism under the 'united states of america' excuse, and B. would have continued to go 'lol segregation and screw you we get the lions share'. Individual Southern states that were white dominated would not want to lose their power.....of course, with the POV of reconstruction being better and longer black america has a plurality of southern legislative offices and militias formed to prevent intimidation and manipulation, aka 'the black nation would stay way stronger'.
an give the African-American economic and political self-sufficiency
under Federal laws and constitution of US, if the racial segregation is respected !
The blacks would have to declare independence (and hopefully they get control of nuclear weapons somehow and hold the white south in a samson plan - and that's a longshot but hey)
At the most under the structure of the current US government they'd get a zone like the zone over Appalachia. I doubt the whites of that era would be happy with admitting 'Black Mississppi' 'Black Georgia' 'Black Alabama' etc, or in a worse case scenario commencing ethnic cleansing of both blacks and whites like the Treaty of Sevres (assuming it isnt done out of a war instead).
Is this "US African American Nation" viably ?
Yes. Black America has enough land in the black belt and enough knowledgeable professionals in order to get some sort of governance.
Not in the mid-20th Century, no, but maybe if Lincoln is not assassianted, he sets aside a territory somewhere out west for freed slaves as an extension of his promise of a mule and 40 acres. Perhaps then, you could have a de facto black nation in North America.
Most slaves were starting to be settled in lands the deposed Slavocracy abandoned until Lincoln was capped....so no.
I take it that the OP means that something like the Bantustans in South Africa could/would occur in the US sometime during segregation?
No, he's looking for something analogous to the Union Republics the Soviet Union had, only for Black America (and id presume other minority groups like Chicanos and Mormons)
Had the Confederacy still existed I don't quite know what would happen.
I'd assume a slave revolt a la Haiti would happen, eventually....[e.g. the slaves started rioting in Brazil and slavery was abolished as the ruling class realized they had no choice, either that or see their society destroyed]