I have dealt with Asians, I have dealt with Hispanics and I have dealt with Blacks. IMHO importing slaves were the worst short term and long term act the Americans ever made.. We should have imported the railroad workers, domestic servants, laundry workers, vegetable gardeners instead. Today we would have a frugal, well to do upper middle class that is well educated, Confucious based family value system and offer high tech skills then dealing with crime, depravity and give us entitlements or else rabble.
Ending the trans-Atlantic slave trade was the best thing Britain ever did for this country. And ending chattel slavery was the best thing Lincoln did for this country. If not for these two actions, this country would be an oversized version of the Caribbean countries - perpetually poor, with a tiny non-black minority that is gradually being squeezed out.