If the price of slaves comes down, then the permanency of the institution comes down. Why? Because every man values his property in proportion to its actual intrinsic worth. . . . Would you be willing to shoulder your musket in vindication of slaveholding rights -- would you be willing to fight for them and risk your domestic peace and happiness if your slaves were only worth five dollars apiece? Why, every man sees that that is an absurdity. Therefore, the permanence of the system depends on keeping the prices high.
Henry S. Foote, quoted in Debow's Review, Vol. 27, Issue 2 (August 1859), p. 219.