When fifty-five delegates gathered in Philadelphia during the sweltering summer of 1787, they faced a challenge that would haunt American politics for the next eight decades. The question wasn’t whether slavery was morally right—many delegates privately acknowledged its evil—but whether a unified nation could exist with slavery as a part of it. That summer, the institution of slavery nearly killed the Constitution before it was born.
The Battle Lines
The convention revealed a stark divide. On one side stood delegates who spoke forcefully against slavery, though they represented a minority voice. Gouverneur Morris of Pennsylvania delivered some of the most scathing condemnations, calling slavery a “nefarious institution” and “the curse of heaven on the states where it prevailed.” According to James Madison’s notes, Morris argued passionately that counting enslaved people for representation would mean that someone “who goes to the Coast of Africa, and in defiance of the most sacred laws of humanity tears away his fellow creatures from their dearest connections & damns them to the most cruel bondages, shall have more votes in a Government instituted for protection of the rights of mankind.”
Luther Martin of Maryland, himself a slaveholder, joined Morris in opposition. He declared the slave trade “inconsistent with the principles of the revolution and dishonorable to the American character.”. Even George Mason of Virginia, who owned over 200 enslaved people, denounced slavery at the convention, warning that “every master of slaves is born a petty tyrant” and that it would bring “the judgment of heaven on a country.”
The Southern Coalition
Facing these critics stood delegates from the Deep South—primarily South Carolina and Georgia—who made it abundantly clear that protecting slavery was non-negotiable. The South Carolina delegation was particularly unified and aggressive in defending the institution. All four of their delegates—John Rutledge, Charles Pinckney, Charles Cotesworth Pinckney, and Pierce Butler—owned slaves, and they spoke with one voice.
Charles Cotesworth Pinckney stated bluntly: “South Carolina and Georgia cannot do without slaves.” John Rutledge framed it even more starkly: “The true question at present is, whether the Southern States shall or shall not be parties to the Union.” The message was unmistakable—attempt to restrict slavery, and there would be no Constitution and perhaps no United States.
The Southern states didn’t just defend slavery; they threatened to walk out repeatedly. When debates over the slave trade heated up on August 22, delegates from North Carolina, South Carolina, and Georgia stated they would “never be such fools as to give up” their right to import enslaved Africans. These weren’t idle threats—they were credible enough to force compromise.
The Three-Fifths Compromise
The central flashpoint came over representation in Congress. The new Constitution would base representation on population, but should enslaved people count? Southern states wanted every enslaved person counted fully, which would dramatically increase their congressional power. Northern states argued that enslaved people—who had no rights and couldn’t vote—shouldn’t count at all.
The three-fifths ratio had actually been debated before. Back in 1783, Congress had considered using it to calculate state tax obligations under the Articles of Confederation, though that proposal failed. James Wilson of Pennsylvania resurrected the idea at the Constitutional Convention, suggesting that representation be based on the free population plus three-fifths of “all other persons”—the euphemism they used to avoid writing the word “slave” in the Constitution.
The compromise passed eight states to two. New Jersey and Delaware are generally identified as the states voting against the compromise, New Hampshire is not listed as taking part in the vote. Rhode Island did not send a delegation to the convention and by the time of the vote New York no longer had a functioning delegation.
Though the South ultimately accepted the compromise, it wasn’t what they wanted. Southern delegates had pushed to count enslaved people equally with free persons—but otherwise ignored on all issues of human rights. The three-fifths ratio was a reduction from their demands—a limitation on slave state power, though it still gave them substantial advantage. With about 93% of the nation’s enslaved population concentrated in just five southern states, this compromise increased the South’s congressional delegation by 42%.
James Madison later recognized the compromise’s significance. He wrote after the convention: “It seems now to be pretty well understood that the real difference of interests lies not between the large and small but between the northern and southern states. The institution of slavery and its consequences form the line of discrimination.”
Could the Constitution Have Happened Without It?
Here’s where I need to speculate, but I’m fairly confident in this assessment: no, the Constitution would not have been ratified without the three-fifths compromise and related concessions on slavery.
The evidence is overwhelming. South Carolina and Georgia delegates stated explicitly and repeatedly that they would not join any union that restricted slavery. Alexander Hamilton himself later acknowledged that “no union could possibly have been formed” without the three-fifths compromise. Even delegates who despised slavery, like Roger Sherman of Connecticut, argued it was “better to let the Southern States import slaves than to part with them.”
The convention negotiated three major slavery compromises, all linked. Beyond the three-fifths clause, they agreed Congress couldn’t ban the international slave trade until 1808, and they included the Fugitive Slave Clause requiring the return of escaped enslaved people even from free states. These deals were struck together on August 29, 1787, in what Madison’s notes reveal was a package negotiation between northern and southern delegates.
Without these compromises, the convention would likely have collapsed. The alternative wouldn’t have been a better Constitution—it would have been no Constitution at all, potentially leaving the thirteen states as separate nations or weak confederations. Whether that would have been preferable is a profound counterfactual question that historians still debate.
The Impact on Early American Politics
The three-fifths compromise didn’t just affect one document—it shaped American politics for decades. Its effects were immediate and substantial.
The most famous early example came in the presidential election of 1800. Thomas Jefferson defeated John Adams in what’s often called the “Revolution of 1800″—the first peaceful transfer of power between opposing political parties. But Jefferson’s victory owed directly to the three-fifths compromise. Virginia’s enslaved population gave the state extra electoral votes that proved decisive. Historian Garry Wills has speculated that without these additional slave-state votes, Jefferson would have lost. Pennsylvania had a free population 10% larger than Virginia’s, yet received 20% fewer electoral votes because Virginia’s numbers were inflated by the compromise.
The impact extended far beyond that single election. Research shows the three-fifths clause changed the outcome of over 55% of legislative votes in the Sixth Congress (1799-1801). (The additional southern representatives—about 18 more than their free population warranted—gave the South what became known as the “Slave Power” in Congress.
This power influenced major legislation throughout the antebellum period. The Indian Removal Act of 1830, which forcibly relocated Native Americans to open land for plantation agriculture, passed because of margins provided by these extra southern representatives. The Missouri Compromise, the Kansas-Nebraska Act, and numerous other slavery-related measures bore the fingerprints of this constitutional imbalance.
The compromise also affected Supreme Court appointments and federal patronage. Southern-dominated Congresses ensured pro-slavery justices and policies that protected the institution. The sectional tensions it created led directly to later compromises—the Missouri Compromise of 1820, the Compromise of 1850—each one a temporary bandage on a wound that wouldn’t heal.
By the 1850s, the artificial political power granted to slave states had become intolerable to many northerners. When Abraham Lincoln won the presidency in 1860 without carrying a single southern state, southern political leaders recognized they had lost control of the federal government. Senator Louis Wigfall of Texas complained that non-slaveholding states now controlled Congress and the Electoral College. Ten southern states seceded in large part because they believed the three-fifths compromise no longer protected their interests.
The Bitter Legacy
The framers consciously avoided using the words “slave” or “slavery” in the Constitution, recognizing it would “sully the document.” But the euphemisms fooled no one. They had built slavery into the structure of American government, trading moral principles for political union.
The Civil War finally resolved what the Constitutional Convention had delayed. The Thirteenth Amendment abolished slavery in 1865, but not until 1868 did the Fourteenth Amendment finally strike the three-fifths clause from the Constitution, requiring that representation be based on counting the “whole number of persons” in each state.
Was it worth it? That’s ultimately a question of values. The Constitution created a stronger national government that eventually abolished slavery, but it took 78 years and a war that killed over 600,000 Americans. As Thurgood Marshall noted on the Constitution’s bicentennial, the framers “consented to a document which laid a foundation for the tragic events which were to follow.”
The convention delegates knew what they were doing. They chose union over justice, pragmatism over principle. Whether that choice was necessary, wise, or moral remains one of the most contested questions in American history.
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Sources
- https://www.battlefields.org/learn/articles/slavery-and-constitution
- https://en.wikipedia.org/wiki/Luther_Martin
- https://schistorynewsletter.substack.com/p/7-october-2024
- https://www.americanacorner.com/blog/constitutional-convention-slavery
- https://www.nps.gov/articles/000/constitutionalconvention-august22.htm
- https://en.wikipedia.org/wiki/Three-fifths_Compromise
- https://www.brennancenter.org/our-work/analysis-opinion/electoral-colleges-racist-origins
- https://www.gilderlehrman.org/history-resources/teaching-resource/historical-context-constitution-and-slavery
- https://www.nps.gov/articles/000/constitutionalconvention-august29.htm
- https://www.lwv.org/blog/three-fifths-compromise-and-electoral-college
- https://www.aaihs.org/a-compact-for-the-good-of-america-slavery-and-the-three-fifths-compromise-part-ii/