Slave Trade

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.

Article I, Section 9, Clause 1

Although the first debate over slavery at the Constitutional Convention concerned representation (see Article I, Section 2, Clause 3), the second debate arose when Southern delegates objected that an unrestricted congressional power to regulate commerce could be used against Southern commercial interests to restrict or outlaw the slave trade. That the resulting provision was an important compromise is underscored by the fact that the clause stands as the first independent restraint on congressional powers, prior even to the restriction on the power to suspend the writ of habeas corpus.

Taking Southern concerns into consideration, the draft proposed by the Committee of Detail (chaired by John Rutledge of South Carolina) dealt with trade issues as well as those relating to slavery. The draft permanently forbade Congress to tax exports, to outlaw or tax the slave trade, or to pass navigation laws without two-thirds majorities in both houses of Congress. Several delegates strongly objected to the proposal, including Gouverneur Morris, who delivered one of the Convention's most spirited denunciations of slavery, calling it a "nefarious institution" and "the curse of heaven."

When the issue came up for a vote, the Southern delegates themselves were sharply divided. George Mason of Virginia condemned the "infernal traffic," and Luther Martin of Maryland saw the restriction of Congress's power over the slave trade as "inconsistent with the principles of the Revolution and dishonorable to the American character." But delegates from Georgia and South Carolina announced that they would not support the Constitution without the restriction, with Charles Pinckney arguing that failing to include the clause would trigger "an exclusion of South Carolina from the Union."

Unresolved, the issue was referred to the Committee of Eleven (chaired by William Livingston of New Jersey), which took the opposite position and recognized a congressional power over the slave trade, but recommended that it be restricted for twelve years, and allowed a tax on slave importation. Although that was a significant change from the Committee of Detail's original proposal, Southern delegates accepted the new arrangement with the extension of the time period to twenty years, from 1800 to 1808.

Agitation against the slave trade was the leading cause espoused by the antislavery movement at the time of the Constitutional Convention, so it is not surprising that this clause was the most immediately controversial of the so-called slave clauses of the proposed Constitution (see Article I, Section 2, Clause 3; Article IV, Section 2, Clause 3; and Article V). Although some denounced the Slave Trade Clause as a major concession to slavery interests, most begrudged it to be a necessary and prudent compromise. James Madison, for example, argued at the Convention that the twenty-year exemption was "dishonorable," but in The Federalist No. 42, he declared that it was "a great point gained in favor of humanity, that a period of twenty years may terminate for ever within these States" what he called an "unnatural traffic" that was "the barbarism of modern policy."

Some claimed that the Commerce Clause gave Congress the power to regulate both the interstate and the foreign slave trade once the twenty-year period had lapsed. James Wilson of Pennsylvania argued, "yet the lapse of a few years, and Congress will have power to exterminate slavery from within our borders." Though the question was not clearly resolved at the time, Madison denied this interpretation during the First Congress. Not even Abraham Lincoln claimed that congressional power to regulate commerce could be used to restrict interstate commerce in slaves.

In Dred Scott v. Sandford (1857), Chief Justice Roger B. Taney pointed to this clause, along with the so-called Fugitive Slave Clause (Article IV, Section 2, Clause 3), as evidence that slaves were not citizens but were to be considered property according to the Constitution. Observers are virtually unanimous that those clauses did not address the question of citizenship at all. Although protection of the slave trade was a major concession demanded by proslavery delegates, the final clause was not a permanent element of the constitutional structure, but a temporary restriction of a delegated federal power. Moreover the restriction applied only to states existing at the time, not to new states or territories, and it did not prevent states from restricting or outlawing the slave trade for themselves. As the dissent in Dred Scott points out, there were freed blacks who were citizens in a number of Northern states and who had voted to ratify the new constitution.

It is significant that the words slave and slavery are not used in the Constitution of 1787, and that the Framers used the word person rather than property. This would assure, as Madison explained in The Federalist No. 54, that a slave would be regarded "as a moral person, not as a mere article of property." It was in the context of the slave trade debate at the Constitutional Convention that Madison argued that it was "wrong to admit in the Constitution the idea that there could be property in men."

Although Southern delegates hoped opposition would weaken with time, the practical effect of the clause was to create a growing expectation of federal legislation against the practice. Congress passed, and President Thomas Jefferson signed into law, a federal prohibition of the slave trade, effective January 1, 1808, the first day that Article I, Section 9, Clause 1, allowed such a law to go into effect.

Profile photo of Matthew Spalding
Matthew Spalding
Vice President, American Studies
Director, B. Kenneth Simon Center for Principles and Politics
B. Kenneth Simon Center for Principles and Politics
The Heritage Foundation