By Allen C. Guelzo, Ph.D., Gettysburg College
It was legal to own slaves in America in 1780s, with just one exception of Massachusetts. So, it wasn’t a surprise that some delegates in the Constitutional Convention owned more than 100 slaves. The war against the mighty British empire had made the Americans question the relevance of slavery in the newly independent nation. Did this new perspective make them question the idea of liberty?

Rufus King and the Revolution
Rufus King’s family had owned slaves, and Rufus King himself had owned at least one slave in his 32 years. But the Revolution had painted the Newburyport, Massachusetts lawyer into a tight ideological spot, since it was difficult to reconcile owning slaves with protests against a British monarch for treating Americans like slaves.
Rufus King was midway through Harvard when the Revolution broke out, but he stayed with his books, and it was not until 1778 that he was recruited to serve, briefly, as an aide on the staff of General John Glover. By 1780, Rufus King was back at the books—in this case, the law books—and hung out his shingle as a lawyer.
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Rufus King and the Confederation Congress
King was elected to the Massachusetts state legislature in 1783, and then to the Confederation Congress in 1784.
However, he continued to be nagged by the incongruity of slave owning in the midst of a revolution for liberty, and in 1785, it was King’s motion in the Confederation Congress that required “that there shall be neither slavery nor involuntary servitude is any of the States” to be formed in the future from the Northwest Territories.
In that respect, King was actually more typical than one might think of the Constitutional Convention.
The Status of Slavery in 1780s
Slavery was legal in all the states in the 1780s but Massachusetts. Vermont instituted partial abolition of slavery in 1777, but it did not actually join the United States until 1791. And even then, slavery was not completely expunged, especially from Vermont, because Vermont did not pass a law explicitly abolishing slavery until 1858.
A rough count of the number of slaves in the entire republic would have yielded approximately 6,50,000, or one-sixth of the American population. Although much of this slave owning was concentrated in the South—half of all American slaves lived and toiled in Virginia—even Pennsylvania, which had begun a gradual emancipation plan in 1780, still had a slave population of 3,700 at the time of the Convention.
Learn more about the Stono Rebellion of 1739.
Slave Owners in the Constitutional Convention
Of the 55 delegates selected for the Convention, just under half of them were slave owners. The majority came from the southern states: from Maryland, Virginia, South Carolina, and Georgia. Still, all the members of the Delaware delegation had owned slaves, and so had a scattering of northerners like King. William Paterson’s family had owned three slaves; Paterson himself still owned one slave on the eve of the Convention.
Moreover, of the 26 slave owners in the Constitutional Convention, 19 of them relied heavily on their slaves as agricultural workers to provide their livelihood and leisure. Five of them—George Mason, John Rutledge, Pierce Butler, Charles Pinckney, and Edmund Randolph—owned more than 100 slaves, and overall, members of the Convention had more money invested in slaves than in the bonds and notes of their own government.
All of this, despite the fact that Americans understood very clearly that slavery was a horror, and was the diametric opposite of the liberty they so much cherished.
The New Perspective on Slavery

William Paterson emancipated his slave, and in 1798 would write the legislation which began the process of freeing all of New Jersey’s slaves. Patrick Henry owned 30 slaves by the time he wished for liberty or death, but he could not deny that slavery was “a practice so totally repugnant to the first impressions of right and wrong.”
James Madison was also feeling uneasy about slavery. In November 1780, while the Revolution was still in full tilt, Madison asked whether “it might not be as well to liberate and make soldiers at once of the blacks? It would certainly be more consonant to the principles of liberty, which ought never to be lost sight of in a contest for liberty.”
By 1785, Charles Thomson, the secretary of the Confederation Congress, could predict to Thomas Jefferson that slavery was “a cancer that we must get rid of. It is a blot in our character that must be wiped out.”
Learn more about the Grand Committee’s report on slavery.
The Dissonance between Liberty and Slavery
There were other signs, too, that the dissonance between liberty and slavery was taking its toll on American patience. The first evidence of this dissonance came hard on the heels of independence, as all but three of the states began to enact bans on the importation of slaves.
In Massachusetts, a proposed state constitution in 1778 would have explicitly legalized slavery there. It was, however, rejected, and a rewritten constitution in 1780 instead began with the declaration that “all men are born free and equal, and have certain natural, essential and inalienable rights; among which may be reckoned the right of enjoying and defending their lives and liberties.”
In 1780, the Pennsylvania Assembly passed a gradual emancipation bill “to extend a portion of that freedom to others, which hath been extended to us.” However, the Pennsylvania bill did not actually abolish slavery; it proposed to phase it out by stages, keeping existing slaves as slaves, and the children of those slaves as slaves until they reached the age of 28, and only immediately freeing the children of slaves born after the passage of the bill.
But by 1784, Benjamin Franklin, who had once owned slaves himself, was telling potential immigrants to America to forget immigrating if they thought that they could come and expect slaves to do their work for them.
Common Questions about Slavery or Liberty: The Moral Dilemma for the Constitutional Convention
Charles Thomson believed that slavery was “a cancer that we must get rid of. It is a blot in our character that must be wiped out.”
Of the 55 delegates selected for the Constitutional Convention, 26 were slave owners, with 5 of them owning more than 100 slaves.
The first evidence of the dissonance between liberty and slavery was when all but three of the states began to enact bans on the importation of slaves.