The Three-Fifths and Slave Trade Compromises

At the 1787 convention, delegates needed a formula for turning each state's population into House seats, and House seats into electoral votes. Northern states with few enslaved people wanted enslaved people left out of the count entirely, since that would shrink Southern representation. Southern states wanted enslaved people counted the same as free people, since that would inflate their seats and votes while enslaved people themselves could not vote. The compromise split the difference: count free residents fully, then add three-fifths of the enslaved population to get a state's counted population for both the House and the Electoral College.

This is why three-fifths made slave states more powerful, not less. The real comparison is not three-fifths versus a whole person. It is three-fifths versus zero. Any fraction above zero added seats and votes that slave states would not have gotten if enslaved people, who could not vote, had simply been excluded from the count. A higher enslaved population meant more House seats, which also meant more electoral votes, since each state's electoral votes equal its House seats plus two. The ratio was a political bargain over power, not a moral claim about a person's value.

The compromise sits next to the slave trade compromise, which let the importation of enslaved people continue until at least 1808, protecting the same Southern interest from another angle. Together they show the convention trading away a chance to limit or acknowledge the wrong of slavery in order to hold the union together, a tension that reappears whenever new states enter and the free-slave balance in Congress shifts again.