Smith explains some features of the slave trade and the constitutional provision that it would not be banned in America for at least 20 years.

George H. Smith was formerly Senior Research Fellow for the Institute for Humane Studies, a lecturer on American History for Cato Summer Seminars, and Executive Editor of Knowledge Products. Smith’s fourth and most recent book, The System of Liberty, was published by Cambridge University Press in 2013.

In The Problem of Slavery in the Age of Revolution, 1770–1823, the eminent historian of slavery David Brion Davis wrote:

The “true” meaning of the Constitution’s provisions on slavery cannot be known, precisely because they were products of an uneasy bargain and were deliberately shrouded in ambiguity. Agreement on concrete economic issues, or in blunter terms, a deal, could not resolve an unnegotiable conflict over the future of American slavery.

Consider the ambiguity in this clause from Article I, section 9.

The Migration or Importation of such Persons as any of the States now existing shall think proper to admit, shall not be prohibited by the Congress prior to the Year one thousand eight hundred and eight, but a Tax or duty may be imposed on such Importation, not exceeding ten dollars for each Person.

In Article V, this clause is one of two in the Constitution that is specifically rendered exempt from amendments: “[N]o Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article….” The other clause included in this exemption—the fourth clause of Article I, section 9—states: “No Capitation, or other direct Tax shall be laid, unless in Proportion to the Census or Enumeration herein directed to be taken.” Proslavery delegates feared that a high tax might be imposed on slaves imported from Africa, and that this tactic might be used by antislavery legislators to render slavery too expensive to be practical, so this clause was inserted to preclude that possibility.

Article I, section 9 mandates that the international slave trade to America may not be prohibited until 1808. Although the slave trade was in fact outlawed in 1808, the clause was sufficiently ambiguous to allow both sides to proclaim victory when speaking before their respective ratifying conventions. It also provided a number of antislavery Antifederalists with an effective talking point against the Constitution. Here is how one Antifederalist, writing under the pseudonym “Brutus,” put it:

What adds to the evil [of the three‐​fifths rule in Article I, section 2] is, that these [slaveholding] states are to be permitted to continue the inhuman traffic of importing slaves, until the year 1808—and for every cargo of these unhappy people, which unfeeling, unprincipled, barbarous, and avaricious wretches, may tear from their country, friends, and tender connections, and bring into those states, they are to be rewarded by having an increase in the general assembly [the House of Representatives].

The horrors of the slave trade were well known to Americans by the time of the Philadelphia Convention in 1787. The atrocities had been widely reported by early antislavery activists, such as the Quaker Anthony Benezet (1713–84). In Some Historical Account of Guinea (1771), Benezet quoted eyewitness accounts of the cruelties practiced aboard slavers. For example, according to a surgeon on board one slaver, after several male captives and one woman had attempted to rise up against their captors, the captain sentenced them to a “cruel death, making them first eat the heart and liver of one of those he had killed. The woman he hoisted by the thumbs, whipped, and slashed with knives before the other slaves till she died.”

After telling another story of hundreds of Africans who were burned alive because their shackles had prevented them from jumping overboard from a burning ship, Benezet commented:

Now here arises a necessary query to those who hold the balance of justice and who must be accountable to God for the use they have made of it….Why are the masters of vessels thus suffered to be the sovereign arbiters of the lives of the miserable Negroes and allowed with impunity thus to destroy (may I not properly say, to murder) their fellow creatures; and that by means so cruel as cannot be even related but with shame and horror?

Many Africans had already been enslaved by native African princes before being sold to Europeans and Americans. This preexisting condition allowed pious Christian captains of slavers (including some Quakers) to justify their transportation of slaves by claiming that the unfortunate victims would be better off in a new land under Christian masters. One devout master of a slave ship, John Newton, read prayers to his crew twice a day, though he admitted that he occasionally employed thumb screws to elicit obedience. Newton, who later became vicar of an Anglican church in London, was fond of writing hymns. One of his better hymns, “How sweet the name of Jesus sounds,” was written during a slaving voyage. Newton did not attempt to justify his job as captain of a slaver. On the contrary, he remarked that he knew of “no method of getting money, not even that of robbing for it upon the highway, which has so direct a tendency to efface the moral sense.” Nevertheless, it was poor health, not moral qualms, that eventually caused Newton to retire as a slave captain.

We should not suppose that the average sailor served on a slaver in the hope of making high wages. Their wages were low, and their treatment by officers brutal. Much of the crew was typically shanghaied; after passing out from drinking, they were carried to a slaver, forced into service, and thereafter treated little or no better than the slave cargo. Indeed, the mortality rate among the crew could be higher than among the slaves. As Hugh Thomas wrote in The Slave Trade: The Story of the Atlantic Slave Trade (1997, p. 311):

Deaths were rarely less than a fifth of the crew, sometimes more: the Nymphe in 1741 lost twenty‐​eight out of forty‐​five; the Couéda arrived at Cap Francois in 1766 with only nine crew members. Perhaps the record was the Marie‐​Gabrielle of Nantes, which in 1769 lost thirty‐​one sailors out of thirty-nine….Analysis of the Dutch slave trade suggests that about 18 percent of crews died on their recorded voyages—in comparison with 12 percent of the slaves. Something like the same statistic must have been true of the English trade: for example, over 20 percent of English crews died on Bristol and Liverpool slavers in the 1780s. But the crews had a longer time on board than the slaves did.

No delegate to the Constitutional Convention needed to be lectured on the barbaric inhumanity of the slave trade. Indeed, Thomas Jefferson protested it in his “original rough draught” of the grievances listed in the Declaration of Independence. This passage, which was entirely deleted by Congress and so doesn’t appear in the final draft, claims that the King of Great Britain had vetoed colonial efforts to outlaw the slave trade:

he has waged cruel war against human nature itself, violating it’s [sic] most sacred rights of life & liberty in the persons of a distant people who never offended him, captivating & carrying them into slavery into another hemisphere, or to incur miserable death in their transportation thither. [T]his piratical warfare, the opprobrium of infidel powers, is the warfare of the CHRISTIAN king of Great Britain, determined to keep open a market where MEN should be bought & sold, he has prostituted his negative [i.e., veto power] suppressing every legislative attempt to prohibit or to restrain this execrable commerce: and that this assemblage of horrors might want no fact of distinguished die, he is now exciting those very people to rise in arms among us, and to purchase that liberty of which he has deprived them, by murdering the people upon whom he also obtruded them; thus paying off former crimes committed against the liberties of one people, with crimes which he urges them to commit against the lives of another.

Jefferson was here complaining about the British promise to liberate any slaves that sided with the British against the American Revolution. Although thousands of slaves fled to New York and other British strongholds, many did not receive the favorable treatment they had expected. As George Mason (an antislavery slaveholder from Virginia) observed during the Constitutional Convention, this was fortunate for the Americans. “Had slaves been treated as they might have been by the Enemy, they would have proved dangerous instruments in their hands.” The slave trade had already been outlawed in Virginia and Maryland, and Mason strongly recommended that the slave trade also be prohibited in South Carolina and Georgia (and in all other states) via the Constitution. Some other delegates agreed with Mason, though none seriously advocated a provision that would have outlawed slavery itself. But Mason and his supporters did not get their wish. The slave trade—that “execrable commerce” and “assemblage of horrors,” as Jefferson described it—was given a 20‐​year lease on life as a means of bringing the Deep South into the Union.

Was this guarantee that the slave trade would not be banned for 20 years by a newly formed federal government a victory for either side? As I stated earlier, the provision was sufficiently ambiguous to allow both sides to claim success at the ratifying conventions in their respective states. I shall explore this controversy in my next essay.