I have posted this story here before, but it's relevant, so I'll post it again. A northern man was visiting New Orleans, and at the port he saw men loading cargo into a ship. The black slaves were on the decks, tossing the cargo down to Irish dockworkers belowdecks. He asked the foreman why the slaves were not in the holds, since that was a much more dangerous position. If you caught parcels wrong it could break your back, and workplace injury and death were very common. The foreman told him, "The slaves have value. If we lose one of them, it's a big problem. If one of the Irish dies, though, we get another one, we lose nothing of value, and nobody cares."