There were two reasons that it took a civil war to end slavery. #1, Most of the South’s economy depended on slave labor and #2 much of the North was heavily involved and invested in the slave trade.
That’s why the original Constitution basically ignored, condoned and even protected slavery. As many in the North as in the Shout profited from it and opposed the ending of it.
To boot, blacks in Africa were major suppliers of black slaves they captured and sold to the slave traders.
All facts usually ignored by modern day politicos, (including northern Americans and blacks), who love to point fingers in every direction except at their own historical roots.