Although the United States Constitution has never contained the words "slave" or "slavery" within its text, it dealt directly with American slavery in at least five of its provisions and indirectly protected the institution elsewhere in the document.[1][2]
At the time of the drafting of the Constitution in 1787, and its ratification in 1789, slavery was banned by the states in New England and Pennsylvania and by the Congress of the Confederation in the Northwest Territory, by the Northwest Ordinance. Though slaves were present in other states, most were forced to work in agriculture in the South.
According to H. W. Brands, because of the declining productivity of crops like tobacco due to soil exhaustion, many of the drafters of the Constitution assumed that slavery would die out naturally in the South as it had done in industrialized North. This changed with the invention of the modern cotton gin in 1793, which provided a more sustainable and economically viable crop for Southern plantations.[3][4]
Throughout U.S. history there have been disputes about whether the Constitution was proslavery or antislavery. James Oakes writes that the Constitution's Fugitive Slave Clause and Three-Fifths Clause "might well be considered the bricks and mortar of the proslavery Constitution".[5] "But", Oakes adds, "there was also an antislavery Constitution.... Congress was granted the power to make 'all needful rules and regulations' for the territories, and for decades after ratification hardly anyone doubted that this authorized the federal government to ban slavery from the territories....[6] Then there was the familiar assertion that the principle of fundamental human equality was embodied in the Constitution.... Doesn't the Preamble state that the purpose of the federal government was to 'secure the blessings of liberty' ... ? Similarly, the Fifth Amendment declares that 'no person' could be deprived of life, liberty, or property without due process of law."[7] The Fifth Amendment, however, was a two-edged sword. In Dred Scott v. Sandford, Chief Justice Roger B. Taney held that "the right of property in a slave is distinctly and expressly affirmed in the Constitution".[8]
Oakes continues: "Throughout the decades-long debate over slavery and the Constitution some of the most contentious issues arose over constitutional principles that cannot be found in the actual wording of the Constitution. Nowhere does the Constitution state that Congress cannot 'interfere' with slavery or abolition in a state, yet it was widely agreed that it could not. Nor does the Constitution expressly recognize a right of 'property in man'.... Given that the Constitution was the handiwork of men who disagreed about slavery, it is hardly surprising that it could be—and was—read as both proslavery and antislavery."[9] Oakes' view is that, "depending on which clauses you cite and how you spin them, the Constitution can be read as either proslavery or antislavery".[10]
In The Constitution of the United States: is it pro-slavery or anti-slavery?, Frederick Douglass cites the Notes of Debates in the Federal Convention of 1787 left behind by James Madison in order to describe four provisions of the Constitution that are said to be pro-slavery. In examining the history of how the clauses were debated and structured, he argues either that they are not pro-slavery or that they do not concern slavery.
He argues that the Three-Fifths Clause (Article I, section 2) "deprives [slave] States of two-fifths of their natural basis of representation"; that the Migration or Importation Clause (Article I, section 9) allowed Congress to end the importation of slaves from Africa in 1808; that the Fugitive Slave Clause (Article IV, section 2) does not apply to slaves but rather to "Person[s] held to Service or Labour", which do not include slaves, because a slave "is a simple article of property. He does not owe and cannot owe service. He cannot even make a contract"; and that the clause giving Congress the power to "suppress Insurrections" (Article I, section 8) gives Congress the power to end slavery, "[i]f it should turn out that slavery is a source of insurrection, [and] that there is no security from insurrection while slavery lasts...."