Slave trade in the United States

The internal slave trade in the United States, also known as the domestic slave trade, the Second Middle Passage and the interregional slave trade, was the mercantile trade of enslaved people within the United States. It was most significant after 1808, when the importation of slaves from Africa was prohibited by federal law. Historians estimate that upwards of one million slaves were forcibly relocated from the Upper South, places like Maryland, Virginia, Kentucky, North Carolina, Tennessee, and Missouri, to the territories and states of the Deep South, especially Georgia, Alabama, Louisiana, Mississippi, Arkansas, and Texas.
Economists say that transactions in the inter-regional slave market were driven primarily by differences in the marginal productivity of labor, which were based in the relative advantage between climates for the production of staple goods. The trade was strongly influenced by the invention of the cotton gin, which made short-staple cotton profitable for cultivation across large swathes of the upland Deep South. Previously the commodity was based on long-staple cotton cultivated in coastal areas and the Sea Islands.
The disparity in productivity created arbitrage opportunities for traders to exploit, and it facilitated regional specialization in labor production. Due to a lack of data, particularly with regard to slave prices, land values, and export totals for slaves, the true effects of the domestic slave trade, on both the economy of the Old South and general migration patterns of slaves into southwest territories, remain uncertain. These have served as points of contention among economic historians. The physical effect of forced labor, and social-emotional effect of family separation in American slavery, was profound.

History

The history of the domestic slave trade can very clumsily be divided into three major periods:

1776 to 1808: This period began with the Declaration of Independence and ended when the importation of slaves from Africa and the Caribbean was prohibited under federal law in 1808; the importation of slaves was prohibited by the Continental Congress during the American Revolutionary War but resumed locally afterwards, primarily through the ports of Wilmington, North Carolina, Savannah, Georgia, and Charleston, South Carolina. Some slaves shipped to these ports were resold locally, others were forwarded on the Natchez and New Orleans slave markets of the lower Mississippi.
1808 to Indian removal and invention of long-staple cotton gin : This period of national expansion can arguably be backdated to the Louisiana Purchase of 1803, and includes the cession of Spanish West Florida in 1821. In the years immediately following the War of 1812, the most active slave markets in the deep South were at Algiers, Louisiana, and Natchez, Mississippi. One New Orleans historian found evidence of that the "queen of the trade", as New Orleans was later known, was open for business in the first years of the 19th century, but "it was not till the 1820s had well set in that the number of American slave merchants grew to impressive proportions" and by 1827 "New Orleans had become the chief center of the slave trade in the lower South".
1830s to American Civil War: This period began when the combination of new lands open for settlement and higher profits for cotton growers led to a massive population transfer of enslaved people from the Chesapeake region to the Mississippi River basin. This era also saw the rise of the ever-more vocal and organized abolitionist movement in the United States, as chronicled and publicized by journals like The Liberator, which was established in 1831.
End of the slave trade

The domestic slave trade wilted during American Civil Warthere was a measurable price drop between 1860 and 1862, due to "market uncertainty" discouraging speculators. In May 1861, a "Southern Mississippian" who seemed to oppose secession even though "no man in Mississippi has a larger proportion of his property in negroes" wrote the Louisville Courier that "The secessionists are carrying out the principles and wishes of the abolitionists. Likely negroes could not be sold here at $500 in good money. Negro traders are as scarce here as in Boston." Still, the business remained brisk and prices rose in the protected interior of the CSA, and according to historian Robert Colby, "Confederates nevertheless interpreted the health of the slave trade as embodying that of their nation."
Times got still harder for traders when the Union blockade and total U.S. military control of the Mississippi River prevented the trafficking of people from, say, rural Missouri to New Orleans. But the slave trade, as an integral part of slavery, persisted throughout Confederate-controlled territory until very nearly the end of the war. Ziba B. Oakes was still listing slaves in Charleston, South Carolina newspaper ads in November 1864. A handful of American-flagged ships were still moving enslaved people from Africa to Cuba and Brazil until 1867, when American participation in the slave trade ended once and for all.

Economics

Slavery was a massive element of the U.S. national economy and even more so the economy of the South: "In 1860, enslaved people were worth more than $3 billion to their owners. In today's economy, that would be equivalent to $12.1 trillion or 67 percent of the 2015 U.S. gross domestic product...The unpaid fruits of their labors created an interest so strong that between 1861 and 1865, Confederate leaders staked hundreds of thousands of lives and the future of their civilization on it." As told by historian Frederic Bancroft, "Slave trading was considered a sign of enterprise and prosperity."
File:Emily Ford and Mary Shaw, Burlingame, Kansas, 1913.jpg|thumb|When interviewed in 1913 by Myra Williams Jarrell for the Topeka Star, Emily Ford and Mary Shawn of Burlingame, Kansas, recalled an instance of family separation in American slavery due to the slave trade
The internal slave trade among colonies emerged in 1760 as a source of labor in early America. It is estimated that between 1790 and 1860 approximately 835,000 slaves were relocated to the American South.
The biggest sources for the domestic slave trade were "exporting" states in the Upper South, especially Virginia and Maryland, and as well as Kentucky, North Carolina, Tennessee, and Missouri. From these states most slaves were imported into the Deep South, to the "slave-consuming states," especially Georgia, Alabama, Mississippi, and Louisiana. Robert Fogel and Stanley Engerman attribute the larger proportion of the slave migration due to planters who relocated their entire slave populations to the Deep South to develop new plantations or take over existing ones. Walter Johnson disagrees, finding that only one-third of the population movement south was due to wholesale relocation of slave owner and chattel, while the other two-thirds of the shift was due to the commerce in slaves.

Contributing factors

Soil exhaustion and crop changes

Historians who argue in favor of soil exhaustion as an explanation for slave importation into the Deep South posit that exporting states emerged as slave producers because of the transformation of agriculture in the Upper South. By the late 18th century, the coastal and Piedmont tobacco areas were being converted to mixed crops because of soil exhaustion and changing markets. Because of the deterioration of soil and an increase in demand for food products, states in the upper South shifted crop emphasis from tobacco to grain, which required less labor. This decreased demand left states in the Upper South with an excess supply of labor.

Land availability from Indian removal

With the forced Indian removal by the US making new lands available in the Deep South, there was much higher demand there for workers to cultivate the labor-intensive sugar cane and cotton crops. The extensive development of cotton plantations created the highest demand for labor in the Deep South.

Cotton gin

At the same time, the invention of the cotton gin in the late 18th century transformed short-staple cotton into a profitable crop that could be grown inland in the Deep South. Settlers pushed into the South, expelling the Five Civilized Tribes and other Native American groups. The cotton market had previously been dominated by the long-staple cotton cultivated primarily on the Sea Islands and in the coastal South Carolina Lowcountry. The consequent boom in the cotton industry, coupled with the labor-intensive nature of the crop, created a need for slave labor in the Deep South that could be satisfied by excess supply further north.
The increased demand for labor in the Deep South pushed up the price of slaves in markets such as New Orleans, which became the fourth-largest city in the country based in part on profits from the slave trade and related businesses. The price differences between the Upper and Deep South created demand. Slave traders took advantage of this arbitrage opportunity by buying at lower prices in the Upper South and then selling slaves at a profit after taking or transporting them further south. Some scholars believe there was an increasing prevalence in the Upper South of "breeding" slaves for export. The proven reproductive capacity of enslaved women was advertised as selling point and a feature that increased value.

Resolve financial deficits

Although not as significant as the exportation of slaves to Deep South, farmers and land owners who needed to pay off loans increasingly used slaves as a cash substitute. This had also contributed to the growth of the internal slave trade.

Statistics

Economic historians have offered estimates for the annual revenue generated by the inter-regional slave trade for exporters that range from $3.75 to $6.7 million.
The demand for prime-aged slaves, from the ages of 15 to 30, accounted for 70 percent of the slave population relocated to the Deep South. Since the ages of slaves were often unknown by the traders themselves, physical attributes such as height often dictated demand in order to minimize asymmetric information.
File:Coastwise_slave_shipment_made_from_Baltimore_to_New_Orleans_by_Hope_H._Slatter_on_the_ship_Scotia_in_September_1843_02.jpg|thumb|Partial manifest of a coastwise slave shipment made from Baltimore to New Orleans, by Hope H. Slatter, on the ship Scotia, September 1843
Robert Fogel and Stanley Engerman estimated that the slave trade accounted for 16 percent of the relocation of enslaved African Americans, in their work Time on the Cross. This estimate, however, was severely criticized for the extreme sensitivity of the linear function used to gather this approximation. A more recent estimate, given by Jonathan B. Pritchett, has this figure at about 50 percent, or about 835,000 slaves total between 1790 and 1850. Without the inter-regional slave trade, it is possible that forced migration of slaves would have occurred naturally due to natural population pressures and the subsequent increase in land prices. In 1965, William L. Miller contended that, "it is even doubtful whether the interstate slave traffic made a net contribution to the westward flow of the population." Historian Charles S. Sydnor wrote in 1933, "The number of slaves brought into Mississippi either by slavetraders or by immigrant masters cannot be precisely stated." Robert Gudmestad found that "Disentangling the various strands of forced migration is like trying to untie the Gordian knot. Migration with owners, planter purchase, and the interstate trade blended together to form a seamless whole."