Wright frames his discussion around the "Williams thesis," based on the 1944 book Capitalism and Slavery, focused on the United Kingdom. Williams argued that while slavery played an important role in British capitalism in the 18th century--in particular, the brutalities of slave labor were central to production of sugar and thus to Britain's international trade--by early in the 19th century the British economy and exports had evolved toward manufacture of industrial products, in such a way that slave labor was no longer vital. Wright argues that as the US economy of the 19th century evolved, slavery tended to hold back US economic growth.
To set the stage, let's be clear that the economic activity of slavery was deeply entangled with capitalism. Wright offers an example that will resonate with those of us working in higher education:
The prominence of slave-based commerce for the Atlantic economy provides the background for the arresting connections reported by C. S. Wilder in his book Ebony and ivy, associating early American universities with slavery. The first five colleges in British America were major beneficiaries of the African slave trade and slavery. ‘Harvard became the first in a long line of North American schools to target wealthy planters as a source of enrollments and income’. The reason for what might seem an incongruous liaison is not hard to identify: ‘The American college was an extension of merchant wealth’. A wealthy merchant in colonial America was perforce engaged with the slave trade or slave-based commerce.However, as numerous writers have pointed out over time, the coexistence of slavery with British and American capitalism of the 17th century does not prove that slavery was necessary or sufficient for an emerging capitalism. As many writers have pointed out, historical slavery across what we now call Latin America. At that time, Spain and Portugal (among others) were also active participants in the slave trade, yet their economies did not develop an industrial revolution like that of the UK. Countries all over Latin America were recipients of slaves, like the area that became the US, but those countries did not develop a US-style economy. Clearly, drawing a straight line from slavery to capitalism of the Anglo-American variety would be wildly simplistic.
Wright argues that slavery did seem essential to sugar plantations: "Sugar plantations required slave labour not because of any efficiency advantage associated with that organizational system, but because it was all but impossible to attract free labour to those locations and working conditions." But Wright argues that when it came to cotton (or tobacco or other crops), slavery did not have any particular advantage over free labor. Thus, US cotton plantations run by slave labor did not come into being because they had an economic advantage, but rather because slaveowners saw it as a way to benefit from owning slaves.
The Atlantic economy of the eighteenth century was propelled by sugar, a quintessential slave crop. In contrast, cotton required no large investments of fixed capital and could be cultivated efficiently at any scale, in locations that would have been settled by free farmers in the absence of slavery. Early mainland cotton growers deployed slave labour, not because of its productivity or aptness for the new crop, but because they were already slave owners, searching for profitable alternatives to tobacco, indigo, and other declining crops. Slavery was, in effect, a ‘pre-existing condition’ for the nineteenth-century American South.
It's true that a lot of pro-slavery writers in the 1850s boasted that cotton was essential to the US economy, as a way of arguing that their own role as slave-owners was also essential. But slave-holders also argued that wage labor was exploitative and slavery represented true Christian morality and the Golden Rule. Rather than listening to the explanations of those trying to justify evil, it's more useful to look at what actually happened in history. If it was true that slave-produced cotton was essential to US economic growth,, then end of slavery should have wiped out US economic growth. But it didn't. Wright points to some research literature looking back at the US economy in the 1830s: "Cotton production accounted for about 5 per cent of GDP at that time. Cotton dominated US exports after 1820, but exports never exceeded 7 per cent of GDP during the antebellum period. The chief sources of US growth were domestic. ... [The] cotton staple growth theory has been overwhelmingly rejected by economic historians as an explanation for US growth in the antebellum era."
Similarly, if it was true that slave plantations were the most efficient way of growing cotton, then the end of slavery should have caused the price of cotton to rise on world markets. But it didn't.
The best evidence that slavery was not essential for cotton supply is what happened after slavery’s demise. The wartime and postwar years of ‘cotton famine’ were times of great hardship for Lancashire, only partially mitigated by high-cost imports from India, Egypt, and Brazil. After the war, however, merchants and railroads flooded into the south-east, enticing previously isolated farm areas into the cotton economy. Production in plantation areas gradually recovered, but the biggest source of new cotton came from white farmers in the Piedmont. When the dust settled in the 1880s, India, Egypt, and slave-using Brazil had retreated from world markets, and the price of cotton in Lancashire was back to its antebellum level ...
Again, slave labor on US cotton plantations was for the benefit of the slaveholders, not the US economy as a whole. Indeed, as the 19th century evolved, the US South consistently underperformed as a cotton supplier. Wright points out three reasons.
First, "[t]he region closed the African slave trade in 1807 and failed to recruit free labour,making labour supply inelastic." Why were slaveowners against having more slaves? As Wright points out: "After voting for secession in 1861 by 84 to 14, the Mississippi convention voted down a re-opening resolution by 66 to 13. The reason for this ostensible contradiction is not difficult to identify: to
re-open the African trade was to threaten the wealth of thousands of slaveholders across the South." In short, bringing in more slaves would have reduce the price of existing slaves--so existing slaveowners were against it. In addition, immigrant to the US from, say, 1820 to 1880 overwhelmingly went to free states. Slave states in the southwest "displayed net white outmigration, even during cotton booms, at times when one might have expected a rush of immigration. One result was low population density and a level of cotton production well below potential."
Second, "[s]laveholders neglected infrastructure, so that large sections of the antebellum South were bypassed by the slave economy and left on the margins of commercial agriculture." The middle of the 19th century was a time when the US had a vast expansion of turnpikes, railroads, canals, and other infrastructure often built by state-charted corporations. However, almost all of this contruction occurred in the northern states. Not only were the southern states uninterested, they actively blocked national-level efforts along these lines: "Over time, however, the slave South increasingly assumed the role of obstructer to a national pro-growth agenda. ,,, [S]outhern presidents vetoed seven Rivers & Harbors bills between 1838 and 1860, frustrating the ambitions of entrepreneurs in the Great Lakes states."
Third, "the fixed-cost character of slavery meant that even large plantations aimed at self-sufficiency in foodstuffs, limiting the overall degree of market specialization." One main advantage of slavery in cotton production was that it guaranteed having sufficient labor available at the two key times of the year for cotton: planting and harvesting. But during the rest of the year, most cotton plantations grew other crops and raised livestock
The shortcomings of the South as a cotton producer during this time were clear to some contemporary observers. Wright says: "Particularly notable are the views of Thomas Ellison, long-time chronicler and statistician of cotton markets, who observed in 1858: `That the Southern regions of the United States are capable of producing a much larger quantity of Cotton than has yet been raised is very evident; in fact, their resources are, practically speaking, almost without limit’. What was it that restrained this
potential supply? Ellison had no doubt that the culprit was slavery ..." Third, "the fixed-cost character of slavery meant that even large plantations aimed at self-sufficiency in foodstuffs, limiting the overall degree of market specialization." One main advantage of slavery in cotton production was that it guaranteed having sufficient labor available at the two key times of the year for cotton: planting and harvesting. But during the rest of the year, most cotton plantations grew other crops and raised livestock
The shortcomings of the South as a cotton producer during this time were clear to some contemporary observers. Wright says: "Particularly notable are the views of Thomas Ellison, long-time chronicler and statistician of cotton markets, who observed in 1858: `That the Southern regions of the United States are capable of producing a much larger quantity of Cotton than has yet been raised is very evident; in fact, their resources are, practically speaking, almost without limit’. What was it that restrained this
In short, the slave plantations of the American South were a success for the slaveowners, but not for the US economy. From a broader social perspective, slavery was a policy that scared off new immigrants, ignored infrastructure, and blocked the education and incentives of much of the workforce. These policies are not conducive to growth. As Wright puts it: ""Slavery was a source of regional impoverishment in nineteenth-century America, not a major contributor to national growth."