I would disagree with that. Northern manufacturing was growing at a rapid pace and needed an ever increasing amount of cheap labor for factories and mines and farms and what have you. The North relied on immigrant labor, and often cruelly abused that labor in a way that slave owners wouldn't have dreamed of doing, as the southern supporters around her are oh so fond of telling us. What they overlook is that like immigrants throughout our history, the new arrivals took whatever jobs they could to provide for their families. Their children made a better life than their parents, and the grandchildren thrived even more. Our history is full of stories of children born on small farms in rural areas, who succeed in spite of lack of education, and who become lawyers, businessmen, even presidents. The child of a slave was a slave. His grandchild was a slave and his great-grandchild was a slave. Not a whole lot of upward mobility available there.