Honestly...slavery should have been abolished at the ratification of the Constitution. And to those who'll scream the 3/5th thingy....we could have had our Civil War right then and there and gotten it over with. Obviously, the existing slaves could have stayed and worked in.
I don’t think the descendants of those who went back to Liberia are living the dream.
. . . and then the Brits would have invaded again once they saw that our united front had collapsed.