Jefferson wrote the following letter at a crucial turning point in the history of slavery. Cotton cultivation was spreading extremely rapidly into the Old Southwest--Mississippi, Alabama, Louisiana, and Arkansas--a development which coincided with the decline of the West Indies, once America's major market for all kinds of exports, and the potentious clash between North and South over admitting Missouri as a slave state. In this letter to Lafayette, the author of the Declaration of Independence advances the specious argument that the movement of slaves to the western territories offered the best solution to slavery. This hope of "diffusing" the black slave population to the west and towards Mexico, as a means of solving the problems of slavery and racial coexistence, drew increasing support from the upper South.
The boisterous sea of liberty indeed is never without a wave, and that from Missouri is now rolling towards us; but we shall ride over it as we have all others... It is not a moral question, but one merely of power....
All know that permitting the slaves of the South to spread in the West will not add one being to that unfortunate condition, that it will increase the happiness of those existing, and by spreading them over a larger surface, will dilute the evil everywhere and facilitate the means of getting finally rid of it, an event more anxiously wished by those on whom it presses than by the noisy pretenders to exclusive humanity.