Quite true. Much hinges on this line:

> millions of nominally free men who are scarcely less its thralls than the black slaves themselves

There is an important distinction to be drawn between "thrall" and "slave." (Anyone who has read ASOIAF should know this!). Now, it should be stated right off the bat that "thrall" here is not a legal term. That is, it was not a recognized title in the same way that "slave" was. Instead, this author is using the term to identify what might be called a "wage slave" in today's language. That is, it is a person who ostensibly has rights, but is nonetheless so dependent upon performing their menial labor, that they are unable to exercise those rights. In this line, a thrall is a sort of indentured servant, someone who (like a wage slave) is so dependent on their job that the nominal rights they do possess, they can't really take advantage of.

So, who were these so-called "thralls." Depending on where they lived, they were hillbillies (western North & South Carolina, Western Virginia, Eastern Tennessee, i.e. Appalachia) or crackers (the lowlands in Georgia & Florida). They were poor whites. If they owned land, they didn't own much of it. Many were 1st or 2nd generation Americans. They didn't have ties to the Southern Aristocracy. And because they weren't really qualified to do much more than menial manual labor, they were constantly scrounging because there was a surplus of free manual labor, i.e. slaves.

It's important to remember that the majority of Southern families didn't own slaves (66%), and the majority of Southern families that did own slaves didn't own more than 20 (about 90%), and about 50% owned five slaves or fewer. This means that the majority of the slaves were owned by a very small minority of slaveowners. In terms of slave ownership, this fact sets up a rough economic class system that goes like this:

Super Rich (20 or more slaves), Rich (5-20 slaves), Middle Class (5 or fewer slaves), Lower Class (no slaves).

Per 100 people, here's how the class split up:

• Super Rich - 3 people
• Rich - 14 people
• MC - 16 people
• LC - 66 people

(Side note, it's also interesting to note that in terms of the "super wealthy," the South had about 60% of the wealthiest citizens in all of the US)

The Super Rich ran massive plantations. The Rich ran sizable plantations, or they had large estates with lots of slaves working as servants, the MC tended to own businesses (general stores, warehouses, docks), and the LC tended to, well, not really have anything to do. (This is a pretty cartoonish picture I'm drawing, just so you know.)

Because of various aristocratic notions, the classes (particularly the Super Rich and the Rich) didn't mingle. Each was a society unto itself more or less. The Super Rich married other Super Riches and they attended Super Rich schools or, as was more often the case, had personal tutors. Same with the Riches and the MCs. The LCs didn't have many options in terms of education, and the government of the South (run by the Super Rich and the Rich) had no incentive to provide any help for establishing any schooling. Many of the schools in the South were actually sort of guerrilla affairs, and/or were established and operated by church groups or Northern groups, and these folks were labeled carpetbaggers.

Now say you're a poor Southern white. You'd be pissed by this set-up. It doesn't work for you, and in terms of Southern whites, you are in the majority. And yet, because the majority of all people in the South were actually Black slaves (Edit this is wrong. Should read "a large percentage" or some variation), and these people were legally and ideologically regarded as lower than everybody, the poor, Southern whites often regarded their plight as: well, hey, at least we're not slaves.

Now, when it came to the end of slavery, the Super Rich and the Rich opposed this move because their very way of life depended on it. They couldn't run their massive plantations or their large estates if they had to pay all the labor that ran them. So their vote was no, obviously. Interestingly, though, poor Southern whites (who made up the majority of Confederate forces) also opposed the abolishment of slavery because it would mean that suddenly black slaves would be in basically the same position that they (the poor, Southern whites) had been in during slavery. That is, nominally free, but with little opportunity. Interestingly, during Reconstruction when groups like the Freedmen's Bureau began establishing schools throughout the South, these schools weren't just patronized by newly free blacks, but also by poor, Southern whites.

The absolute best source for much of this information is Eric Foner's fantastic Reconstruction: America's Unfinished Revolution. Additional sources included Heather Andrea Williams' Self-Taught, as well as some dated, but still fascinating books such as The Peculiar Institution by Ken Stampp, American Negro Slavery and Life and Labor in the Old South by UB Phillips. Also, check out the 1860 US Census Data

It's a bit of fact and a bit of propaganda. There are many claims in here, so I'll probably miss some, but let me start with the first big red flag that's demonstrably not true:

And in the blighting shadow of Slavery letters die and art cannot live. What book has the South ever given to the libraries of the world? What work of art has she ever added to its galleries? What artist has she produced…

There were several big names from the south in literature during the Antebellum period. The best example I can think of, William Gilmore Simms, whom Edgar Allen Poe praised as "the best novelist which this country, on the whole, has produced.". The south even had at least one literary magazine that I know of, The Southern Literary Messenger, also edited by Poe for a short time, coincidentally. It's safe to say the south was not suffering for lack of writers during that period.

As for fine arts, I'm struggling to come up with native southern painters who remained in the south through their lives, though I'm not well-versed in art history. If you expand that to painters born elsewhere who worked in the south, I can come up with some like John Audubon and George Caleb Bingham. There are probably others, but I have to admit that art history is totally out of my realm of knowledge.

As for the greater claim of the entire article:

Possessed of all the raw materials of manufactures and the arts, its inhabitants look to the North for everything they need from the cradle to the coffin. Essentially agricultural in its constitution, with every blessing Nature can bestow upon it, the gross value of all its productions is less by millions than that of the simple grass of the field gathered into Northern barns. With all the means and materials of wealth, the South is poor.

There's some truth in that. No, the south did not have much industry outside of agriculture, save for a few places in eastern states like Virginia. However, I'd say it's a stretch to say that the South looked to the North for everything they needed. Most of the whites in the south weren't plantation owners, but subsistence farmers who mostly took care of their own needs. The claim that the difference in economy was due to slavery is mostly true. In order to support industry, you need people to sell things to. Slaves don't need that many goods, so producing goods to sell is less enticing in such a market.

Why are they subjected to a censorship of the press, which dictates to them what they may or may not read, and which punishes booksellers with exile and ruin for keeping for sale what they want to buy? Why must Northern publishers expurgate and emasculate the literature of the world before it is permitted to reach them?

There's a small bit of truth to the censorship, but I only know of one very specific case of censorship. There was an outrage among southerners in 1835 over mailed abolitionist pamphlets, Post Master General Amos Kendall allowed them to be banned them from being mailed to the south. During this time, several southern states also passed laws against distributing abolitionist literature.

The bigger issue here might be that of self-censorship. I think this goes beyond people who might have believed in abolition privately, but publicly denounced it (although those certainly existed as well). Newspapers in the south, even those that took a more liberal stance, seemed unable to reconcile that the system of slavery their part of the country relied on was an inherent evil. A great example of this is Brownlow's Whig, a newspaper created by William Brownlow, who would eventually serve as governor and senator of TN, following the Civil War. I choose Brownlow because he's the perfect example of this confusing dichotomy and the shifting view of some southerners on slavery. When the paper begins in the 1830s, he is decidedly pro-slavery. As the war approaches, he continues to support slavery, but he is staunchly opposed to secession. During and after secession, he continues to oppose secession and in the meantime, his views on slavery shift. First, he begins to admit that Union is more important than slavery before finally taking a flat-out abolitionist stance by the end of the war.

From a transcript published in the July 2, 1864 issue of his paper, illustrating the strange position before advocating complete abolition:

I do now know that I would be willing to go so far as probably he would. But I cordially agree with him in this -- I think, considering what has been done about slavery, taking the thing as it now stands, overlooking altogether, either in the way of condemnation or in the way of approval, any act that has brought us to the point where we are, but believing in my conscience and with all my heart, that what has brought us where we are in the matter of slavery, is the original sin and folly of treason and secession, because you remember that the Chicago Convention itself was understood today and I believe it virtually did explicitly say that they would not touch slavery in the States. ... We are prepared to demand not only that the whole territory of the United States shall not be made slave, but that the General Government, both the war power and the peace power, to put slavery as nearly possible back where it was -- for although that would be a fearful state of society, it is better than anarchy; or else use the whole power of the Government, both of war and peace, and all the practicable power that the people of the United States will give them to exterminate and extinguish slavery.

It's pretty clear that no one told Brownlow not to talk about abolition. His paper was known for being inflammatory and he didn't really care what the authorities had to say. It was shut down and reopened several times over the years as he fled from public backlash, assassination attempts, and eventually the Confederate army. It changed names almost as often as he changed locations including: Tennessee Whig, The Whig, The Jonesborough Whig, The Jonesborough Whig and Independent Journal, The Knoxville Whig and Independent Journal, and perhaps most colorfully, Brownlow's Knoxville Whig and Rebel Ventilator. My point being, it was pretty clear that he didn't care if he upset people and wasn't the type of man who wouldn't talk about abolition because it might against some regulation. He didn't believe in abolition for other, personal reasons until later on. I think this might be indicative of the more widespread form of "censorship" and not talking about abolition.

As far as the entire article, it seems to fall into the old view of looking reasons why the south was backward rather than seeing the north as revolutionary and the south as being more in step with other countries, like those in Europe and Russia. I agree with James McPherson's assessment in Battle Cry of Freedom that the war was the south's counter revolution to an economic, social, and political revolution that was happening in the north. In short: the article presents a heavily biased, though not completely untrue view of the south and its problems.

edit: added more sources and expanded a bit.

I am surprised no one has mentioned the works of Frederick Law Olmsted, well known for his work as a landscape architect, New York's Central Park being perhaps his most famous design.

He was also a farmer in New York, and traveled throughout a good deal of the slave states paying particular attention to agriculture and the general condition of those states. He wrote 3 volumes of close observations of his travel and very keen criticisms of the slave system and its effects on the land and people of all classes. His conclusions very closely agree with the article above.

The three volumes are "A Journey in the Seaboard Slave States" published 1856, "A Journey Through Texas", 1857, and "A Journey in the Back Country in Winter of 1853-4", published 1860.

These books were well received, and his English publisher suggested an 1 volume abridgement which was published in 1861 shortly after the start of the Civil War. This was "Journeys and Exploration in the Cotton Kingdom". It had a new introduction "The Present Crisis" with sharpened criticism.

All these works are readily available in reprint and are fascinating reading, touching on most of the points mentioned in the above article.

This is very late, but I finally regained access to some sources, so here goes.

The last line is actually one of the most salient points in the debate; it's actually true that northern farms generally had higher value of land per acre. However, this misses the point that Southern farms actually had higher cash value on the crops produced, so I think the author was getting ... creative in assessing the wealth of the two sections.

More generally, if you want to look at a 'control test' to compare north and south, Edward Ayers has a fascinating book called Valley of the Shadow; he collected sources on Franklin County PA and Augusta County VA. They're in basically the same valley, but on opposite sides of the Mason Dixon line. Same climate, same soil, same people, with the one difference being slavery, but this one difference in conditions gives rise to radically different societies.

One of the points Ayers makes is that except for the slaves themselves, almost everyone in Augusta benefitted from the slave economy. Rich whites, poor whites, and even free blacks in the South owned considerably more valuable property than their counterparts in the north. Not only did the slaves themselves count as incredibly valuable property, but even those too poor to own slaves could rent them from neighbors with a surplus of slaves.