Smith summarizes the arguments of delegates as to whether the slave trade should be prohibited in the Constitution.

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.

On July 26, 1788, on the floor of the North Carolina Ratifying Convention, a delegate wanted to know why the first clause of the Ninth Section was included in the proposed Constitution. This clause states:

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 Importations, not exceeding ten dollars per Person.

The reason for including this clause was explained by Richard Dobbs Spaight, who had served in the Confederation Congress, in the North Carolina House of Commons, and as a delegate to the Constitutional Convention. Some delegates from the northern states wanted to abolish the slave trade completely and immediately, whereas some delegates from the southern states didn’t want the federal government to interfere in the slave trade at all. Slave labor was essential to the southern economy, so those delegates “would not consent to the desire of the Northern States to exclude the importation of slaves absolutely.”

A compromise was reached. It was agreed that the slave trade would operate unmolested for twenty years, and it was generally understood that the trade would be outlawed in 1808 (which it was). Southern delegates agreed to this compromise because (quoting Spaight) “they were now in want of hands to cultivate their lands,” but “in the course of twenty years they would be fully supplied.” Some delegates in southern ratifying conventions claimed this compromise as a victory for the slave states, because it officially protected and sanctioned slavery on the federal level, if only for a limited period of time.

Antislavery champions of the Constitution had a more difficult time rationalizing the twenty‐​year clause. How could they agree to sanction a practice that they personally regarded as cruel and murderous? How could they boast that the new Constitution was intended to “establish Justice…and Secure the Blessings of Liberty” when it told potential kidnappers and murderers that the federal government would not interfere in their activities for twenty years?

One path was to claim that the twenty‐​year clause was actually a step toward the abolition of slavery. Edmund Randolph, the governor of Virginia who played an important role in the Constitutional Convention, flatly denied this rumor during the Virginia Convention (June 21, 1788). Even South Carolina, Randolph told his follow Virginians, believed the clause provided security for slavery.

Were it right here to mention what passed in the [Philadelphia] convention on the occasion [delegates had been sworn to secrecy], I might tell you that the southern states, even South‐​Carolina herself, conceived this property [in slaves] to be secure by these words. I believe, whatever we may think here, that there was not a member of the Virginia delegation who had the smallest suspicion of the abolition of slavery.

A common excuse given by antislavery types in defense of the twenty‐​year compromise was that slavery was a doomed institution that would eventually die out on its own, regardless of the controversial clause. This was a common assumption well into the nineteenth century, and a substantial increase in the slave population during those decades did little to dampen its popularity. It came up a number of times during the Constitutional Convention, especially during the early stage (May 25 to Sept. 17) when delegates were sitting as a Committee of the Whole. This parliamentary device permitted delegates to express their beliefs candidly, argue with other delegates, and to cast nonbinding votes on measures without committing themselves definitively to those measures. The task of the Committee of the Whole was to make recommendations to the Convention, even though there was no difference in personnel (except for the president). Delegates had little fear that their true opinions might leak out to their constituents and thereby harm them politically. The Convention was conducted behind closed doors, delegates agreed not to discuss the proceedings with the press or public, and they also agreed not to publish their notes for at least fifty years—an agreement that was meant to protect them from future political damage if their real opinions became known. After Jefferson (who was then in France) learned of this secrecy rule, which was vigorously supported by James Madison, George Mason, and other prominent delegates, he protested in a letter to John Adams:

I am sorry [the Convention delegates] began their deliberations by so abominable a precedent as that of tying the tongues of their members. Nothing can justify this example but the innocence of their intentions, and the ignorance of the value of public discussion.

It was on August 22, 1787, while sitting as a Committee of the Whole, that delegates discussed the slave trade more fully than at any other time. Here is a sampling of the opinions expressed, taken from Madison’s notes of the Convention.

George Mason (Virginia) disagreed with the position that the slave trade should be solely a matter for individual states to decide. Slavery was an evil that affected the entire nation, so “the Genl. Govt. should have the power to prevent the increase of slavery.”

Slavery discourages arts & manufacturers. The poor despise labor when performed by slaves. They prevent the immigration of Whites, who really enrich & strengthen a Country. They produce the most pernicious effect on manners. Every master of slaves is born a petty tyrant. They bring the judgment of heaven on a Country. As nations can not be rewarded in the next world they must be in this. By an inevitable chain of causes & effects providence punishes national sins, by national calamities.

Mason was a major slaveholder, so one opponent cleverly implied that his remarks about the moral corruption caused by slaveholding would apply to himself, not only to others. This at least seems to be the import of the opening remark by Oliver Ellsworth (Connecticut): “As he had never owned a slave [he] could not judge of the effects of slavery on character.” Ellsworth also pointed out the hypocrisy of calling for a ban on the slave trade without also calling for the abolition of slavery itself. “He said however that if [slavery] was to be considered in a moral light we ought to go farther and free those already in the Country.” To ban the slave trade would be “unjust” to South Carolina and Georgia. Slaves multiply quickly in Virginia and Maryland, so it is cheaper for those states “to raise then import them, whilst in the sickly rice swamps [of the Deep South] foreign supplies are necessary.” Therefore, “Let us not intermeddle.” Slavery will virtually disappear on its own in any case. “As population increases; poor laborers will be so plenty as to render slaves useless. Slavery in time will not be a speck in our Country.”

Charles Pinckney (South Carolina) attended every session of the Constitutional Convention and was a major participant in the debates. He defended both slavery and the need for a Bill of Rights. Pinckney later claimed that he had written the draft that became the basis of the final Constitution, and his persistent assertions earned him the nickname of “Constitution Charley.” Pinckney justified slavery by appealing to history:

If slavery be wrong, it is justified by the example of the world….In all ages one half of mankind have been slaves. If the S. States were let alone they will probably of themselves stop importations. He wd. himself as a Citizen of South Carolina vote for it. An attempt to take away the right as proposed [by banning the slave trade] will produce serious objections to the Constitution which he wished to see adopted.

Pinckney’s first cousin, Major General Charles Cotesworth Pinckney (South Carolina), served as an aide to George Washington during the War for Independence. He asserted that a ban on the slave trade would mean that the new Constitution would never be ratified in South Carolina, even if southern delegates used all their influence to support it. General Pinckney also repeated the claim that a ban would be prejudicial to South Carolina and Georgia. “S. Carolina and Georgia cannot do without slaves. As to Virginia she will gain by stopping the importations. Her slaves will rise in value, & she has more than she wants.” The slave trade, moreover, is justified on utilitarian grounds; it serves the economic interests of America.

He contended that the importation of slaves would be for the interest of the whole Union. The more slaves, the more produce to employ the carrying trade: the more consumption also, and the more of this the more revenue for the common treasury.

I have sketched only three comments on banning the slave trade; many other delegates expressed their views as well. It is instructive, in my judgment, that justice and injustice were raised only in regard to the slaveholding states, not in regard to the enslaved Africans. Banning the slave trade would supposedly be unjust to South Carolina and Georgia, because it would give an unfair competitive advantage to the other slave states. Presumably “equal rights” in this case meant the equal right of every state to engage in egregious violations of individual rights, including kidnapping and murder. An ominous note was struck by Georgia’s Abraham Baldwin, who had served as a chaplain in the Continental Army. He maintained that the slave trade should be a local rather than a national matter. Georgia was adamant on this issue; she would never ratify a constitution that demanded abolition of the slave trade. But she might eventually “put a stop to the evil” on her own terms, if left alone. This was because a “respectable class of people” was applying “their ethics beyond the mere equality of men, extending their humanity to the claims of the whole animal creation.”

I suppose this comment could be interpreted in various ways, but to me it sounds as if Baldwin was denying that Africans were human beings at all. Their hope lay in the fact that some philosophers were applying rights to beings other than humans. Put in modern terms, the way to defend the rights of slaves was to defend a broad conception of animal rights.