Omniscience is a quality of the Almighty and not of politicians. Had the founders foreseen the invention of the cotton gin a mere six years after the drafting of the Constitution would they have approved a slavery clause? By 1787 slavery was becoming unprofitable – Jefferson would go into bankruptcy as a tobacco planter – no one expected it to last another generation and the slaveholders were probably more concerned about the costs of repatriation than anything else. The idea of deferring a problem that presented huge adverse economic consequences was not invented recently.
Kennedy has written a good book that grasps part of the problem and is worth considering within the whole context of the slavery issue. It presents discrete pieces of the puzzle and the underlying history is far better than the superficial analysis. They say hindsight is 20/20 and if the book has a fault it is that it seems to be using the prism of hindsight rather than the perspective of history.
Mr. Jefferson’s lost cause : land, farmers, slavery, and the Louisiana Purchase New York : Oxford University Press, 2003 Roger G. Kennedy Land settlement Political aspects United States History Hardcover. 1st ed. and printing. xv, 350 p.,  p. of plates : ill., maps ; 25 cm. Includes bibliographical references (p. 312-335) and index. Clean, tight and strong binding with clean dust jacket. No highlighting, underlining or marginalia in text. VG/VG
Thomas Jefferson advocated a republic of small farmers – free and independent yeomen. And yet as president he presided over a massive expansion of the slaveholding plantation system, particularly with the Louisiana Purchase, squeezing the yeomanry to the fringes and to less desirable farmland. Roger G. Kennedy conducts an examination of the gap between Jefferson’s stated aspirations and what actually happened.
Kennedy reveals how the Louisiana Purchase had a major impact on land use and the growth of slavery. He examines the great financial interests (such as the powerful land companies that speculated in new territories and the British textile interests) that beat down slavery’s many opponents in the South itself (Native Americans, black Americans, Appalachian farmers, and other opponents of slavery). He describes how slaveholders’ cash crops – first tobacco, then cotton – sickened the soil and how the planters moved from one desolated tract to the next. Soon the dominant culture of the entire region – from Maryland to Florida, from Carolina to Texas – was that of owners and slaves producing staple crops for international markets.
None of this, Kennedy argues, was inevitable. He focuses on the character, ideas, and ambitions of Thomas Jefferson to show how he and other Southerners struggled with the moral dilemmas presented by the presence of Indian farmers on land they coveted, by the enslavement of their workforce, by the betrayal of their stated hopes, and by the manifest damage being done to the earth itself. Jefferson emerges as a tragic figure in a tragic period.