Until the Civil War settled the issue once and for all, conflict raged between the northern abolitionists and the Southern traditionalists, with Southerners fiercely defending their right to own human beings. Abolitionists contended that the domestic trade was vital to slavery’s survival and exemplified the worst aspects of a totally corrupt system. Slaves, they argued, were inefficient workers because they lacked any positive incentives to work well. Plantation monoculture led to soil exhaustion and therefore slave-based agriculture was hopelessly unprofitable in the Upper South. The abolitionists believed that the slave system was kept alive in the Upper South only through the supplementary incomes gained from trafficking in humans to professional Negro speculators and from deliberately breeding and rearing people for sale.

Interview with Hanna Jones from Missouri Narratives, Volume 10

Alvan Stewart proclaimed that the domestic trade was so important that ending it would break open "the great door to the slave Bastille." Without the long-distance market: "The slaves of Maryland and Virginia would eat up their masters, and the masters must emancipate in self-defense to save themselves from destruction."  As for the Deep South, Stewart prophesied:

"[In Alabama, Louisiana and Mississippi] there is such havoc annually by death among the slaves of the great planters . . . that in less than seven years, if no slave could be imported into those southern regions, one half of the plantations would lie uncultivated for want of slaves. "

The abolitionists viewed white Southerners as inhumanly callous and so deeply corrupted morally that in return for the traders’ cash they were happy to break up families and send individuals on long-distance forced migrations to an assuredly terrible fate.

Those who benefited from the domestic slave trade developed rationalizations to justify their activities. Throughout the years of the trade and for decades thereafter, pro-slavery propagandists maintained that owners only reluctantly - when under financial duress - resorted to selling their slaves and breaking up families. There is ample evidence available to refute this proposition. Traders’ bills of sale suggest that no more than 5 percent of their "stock" were acquired at debt, probate, or other court-mandated sales. Rarely were the owners staving off imminent financial crisis when they sold to the traders. They were, in fact, further increasing their profits.

Records also give the lie to another major claim propounded by slave-trade apologists - that the people they sold were most often recaptured runaways or "criminals" being punished for their transgressions. These groups comprised only a very small portion of the trade. Runaways were nearly always male, while the trade was made up of roughly equal numbers of men and women. The bodies of fugitives and "criminals" would have borne the scars of the lash, and traders would have regarded them as extremely risky buys.

Many owners lived under the delusion that they treated their bondspersons well and were loved and respected by them. They clung to this belief by embracing an absurd rationalization: black people, they claimed, were emotionally shallow and, unlike whites, did not have strong attachments to their families. The history of the slave trade lays bare the mythmaking that made up the "plantation legend."

In the end, the abolitionist position on the slave trade was essentially correct about its size and about the character of its participants. At the same time, they greatly overestimated the problem of the planters’ debts. By buying into the myth that most sales were made to ease the owners’ financial problems, they underestimated the slaveholders’ voluntary participation in the trade. The abolitionists also exaggerated the extent of systematic breeding among the enslaved.

Letters from Thomas Jefferson to Joel Yancey and to John Wayles Eppes on slave breeding

Slaveholders took great interest in the growth of their "stock" of people. But there does not seem to be any significant evidence to support an abolitionist claim that the selling states developed a system of specialist "breeding farms."