By 1790 slavery was on the decline in America. Apart from tobacco, rice, and a special strain of cotton that could be grown only in very few places, the South really had no money crop to export. Tobacco was a land waster, depleting the soil within very few years. Land was so cheap that tobacco planters never bothered to reclaim the soil by crop rotation -- they simply found new land farther west. The other crops -- rice, indigo, corn, and some wheat -- made for no great wealth. Slaves cost something, not only to buy but to maintain, and some ....