Also don't forget that the North was big on importing slaves for a long time, to sell them. miles
That part of the equation is only very rarely, if ever, mentioned by the historians, or those who condemn slavery. Instead, they try and paint a picture of where Ole Massa, Jefferson Davis, and Robert E. Lee sailed over to Africa, abucted some Negroes who were busy designing plans to put a man on the moon, and brought them back to the South to pick cotton.
