The Economics of Slavery

Gavin Wright argues that slavery died out in North and intensified in the South primarily for economic reasons. Slavery thrived where it was economically advantageous for it to do so. "North American colonies had to buy African slaves on a world market at prices which reflected the high profitability of slavery in the sugar colonies of the West Indies. For this reason . . . slavery expanded only in areas where profitable export staples were available."

In the colonies and, later, in the United States, the only such staples that justified the cost were rice, tobacco, indigo and, later, cotton:

There was no inherent incompatibility between slavery and Northern climes and crops; it was strictly a matter of relative returns. The geographic distribution of the free population was determined by a host of social, cultural, legal, and psychological, as well as economic considerations, but as a general rule, slave labor followed the market. This market-determined difference of the eighteenth century became a legal and political distinction in the nineteenth century, as the Northern states all moved toward full abolition of slavery by the 1790s.

Gavin Wright, The Political Economy of the Cotton South: Households, Markets, and Wealth in the Nineteenth Century (New York: W.W. Norton & Co. 1978), at 11-12.