Liberals love to give scathing denunciations of plantation slavery (denunciations I agree with), as well as declare their support of socialism and communism (which I don't agree with). But therein lies an interesting contradiction: Socialism and communism are both organized assaults on economic freedom, which is a feature that they share with plantation slavery.
One of the more ironic ways in which this contradiction manifests itself is when they characterize slavery as bringing great wealth to the economies of the South. (Among the works putting forward this claim are PBS's Andrew Jackson documentary, and their documentary "Slavery and the Making of America.") Why they want to characterize slavery as helpful to the economy is a mystery, but I suspect they want to condemn the entire South (not just the slaveholding Southerners) as profiting from slavery. They may want to say that all wealth in America is owed to the descendants of black slaves, or perhaps even that America's wealth is tainted by its coming from slave labor.
Whatever the reason, the thing that makes this ironic is that slavery greatly hurt the economies of the South; creating enormous wealth for a few individuals, but holding back the economy as a whole. Although liberals (including those in these two programs) give eloquent denunciations of slavery on moral grounds, and moving depictions of individual slave stories; they are ironically agreeing with the slaveholders that slavery benefits the economy - not only paying well for individual slaveholders, but creating great wealth for the country. (That is the liberals' claim.)
It is the conservative defenders of capitalism - and capitalism's Founding Father, Adam Smith - who put forward the theory that slavery hurts an economy; and that its costs are not exclusively moral, but practical as well. I will endeavor to show this with some quotes from "The Wealth of Nations" (Adam Smith's most famous book), and give his arguments against the profitability of slavery as my own.
First of all, Adam Smith did not deny that slavery creates wealth for some individuals - it could otherwise not exist. There has to be some incentive for it to be instigated, and here is Adam Smith's description of why: "The pride of man makes him love to domineer, and nothing mortifies him so much as to be obliged to condescend to persuade his inferiors. Wherever the law allows it, and the nature of the work can afford it, therefore, he will generally prefer the service of slaves to that of freemen." (Source: "The Wealth of Nations," Book III, Chapter II)
Slavery on Virginia tobacco plantation, 1670
But this is not to say that slavery creates wealth for the economy, as liberals claim. In Adam Smith's words:
"The wear and tear of a slave, it has been said, is at the expense of his master; but that of a free servant is at his own expense. The wear and tear of the latter, however, is, in reality, as much at the expense of his master as that of the former. The wages paid to journeymen and servants of every kind must be such as may enable them, one with another to continue the race of journeymen and servants, according as the increasing, diminishing, or stationary demand of the society, may happen to require. But though the wear and tear of a free servant be equally at the expense of his master, it generally costs him much less than that of a slave. ... It appears, accordingly, from the experience of all ages and nations, I believe, that the work done by freemen comes cheaper in the end than that performed by slaves." (Source: "The Wealth of Nations," Book I, Chapter VIII)
He also makes this point in two other ways. Here is the next of them:
"The experience of all ages and nations, I believe, demonstrates that the work done by slaves, though it appears to cost only their maintenance, is in the end the dearest of any. A person who can acquire no property can have no other interest but to eat as much and to labour as little as possible. Whatever work he does beyond what is sufficient to purchase his own maintenance, can be squeezed out of him by violence only, and not by any interest of his own." (Source: "The Wealth of Nations," Book III, Chapter II)
And finally, this quote:
"Such tenants, being freemen, are capable of acquiring property; and having a certain proportion of the produce of the land, they have a plain interest that the whole produce should be as great as possible, in order that their own proportion may be so. A slave, on the contrary, who can acquire nothing but his maintenance, consults his own ease, by making the land produce as little as possible over and above that maintenance." (Source: "The Wealth of Nations," Book III, Chapter II)
Former sugar plantation in the British West Indies, in what is today Jamaica
These quotes give some important context for another quote on slavery, which can easily be taken out of context by Adam Smith's opponents. He said that "The blacks, indeed, who make the greater part of the inhabitants, both of the southern colonies upon the continent and of the West India islands, as they are in a state of slavery, are, no doubt, in a worse condition than the poorest people either in Scotland or Ireland. We must not, however, upon that account, imagine that they are worse fed, or that their consumption of articles which might be subjected to moderate duties, is less than that even of the lower ranks of people in England. In order that they may work well, it is the interest of their master that they should be fed well, and kept in good heart, in the same manner as it is his interest that his working cattle should be so." (Source: "The Wealth of Nations," Book V, Chapter III) This quote could be used by his opponents to paint Adam Smith as saying that the condition of slaves was all right; but he made clear that they are still "in a worse condition" than the poorest people in Scotland or Ireland, and - as the previous quotes demonstrate - slave labor is not as cheap as it's often made out to be. All this slaveholder nonsense (echoed by modern liberals) about slave labor benefiting the economy is hogwash, in short.
Another quote like these is easily taken out of context, to paint Adam Smith as considering blacks inferior; but the latter part of the quote shows that he is far from this - even the very opposite of a racist. The first sentence is the part easily taken out of context, but the rest of it shows what he really said: "Slaves, however, are very seldom inventive; and all the most important improvements, either in machinery, or in the arrangement and distribution of work, which facilitate and abridge labour have been the discoveries of freemen. Should a slave propose any improvement of this kind, his master would be very apt to consider the proposal as the suggestion of laziness, and of a desire to save his own labour at the master's expense. The poor slave, instead of reward would probably meet with much abuse, perhaps with some punishment. In the manufactures carried on by slaves, therefore, more labour must generally have been employed to execute the same quantity of work, than in those carried on by freemen. The work of the former must, upon that account, generally have been dearer than that of the latter." (Source: "The Wealth of Nations," Book IV, Chapter IX) In a word, being free - and generously rewarded for one's labor - makes one more profitable. A black person who is free, will be more productive than one who is enslaved.
The Roman emperor Augustus, referenced below
One part which shows some great sympathy for American slaves is this one: "That the condition of a slave is better under an arbitrary than a free government, is, I believe, supported by the history of all ages and nations. In the Roman history, the first time we read of the magistrate interposing to protect the slave from the violence of his master, is under the emperors. When Vidius Pollio, in the presence of Augustus, ordered one of his slaves, who had committed a slight fault, to be cut into pieces and thrown into his fish-pond, in order to feed his fishes, the emperor commanded him, with indignation, to emancipate immediately, not only that slave, but all the others that belonged to him. Under the republic no magistrate could have had authority enough to protect the slave, much less to punish the master." (Source: "The Wealth of Nations," Book IV, Chapter VII, Part II) As the black historian Gerald Early put it; "African-Americans were legally a people who have a legacy, a history, a historical consciousness of having been un-free in a free country." (Source: Ken Burns' "Jazz," Episode 1, 10min14sec-10min33sec)
So in summary, Adam Smith had a much greater opposition to slavery than his liberal critics today like to paint - he was a complete opponent of it. He believed that slavery hurts an economy, whereas slaveholders then - and liberals now - consider it profitable to society. Liberals claim it "brings great wealth to an economy," whereas Adam Smith knows the truth: Assaults on economic freedom always do great damage to a country's economy. This is why socialism and communism don't work - because they assault economic freedom almost as much as plantation slavery did. The real opposition to slavery today comes from supporters of the free market, who are the intellectual heirs of Adam Smith.
Why Adam Smith is still relevant today