The three-fifths clause of the US Constitution was an agreement among states made in 1787 on the representation in the US House of Representatives.
In May of 1787, delegates from 12 of the 13 states met in Philadelphia at the Constitutional Convention. Their goal was to come up with an outline for the entire government of the US, and their biggest challenge was representation. The question that came up in the Constitutional Convention was: “how would states be represented in the new Congress under the Articles of Confederation.”
During this time, slavery was still a significant issue in the country. In most southern states, the enslaved population made up a large percentage of the total population. Since a considerable amount of their population was made up of slaves, southern states wanted their slave population to count towards the representation in the House of Representatives. The higher the population, the more representatives they would receive. On the other hand, the southern states did not want their enslaved population to count toward their taxes. The higher the population, the more taxes they would have to pay.
The northern states disagreed with the southern ones on both issues. There were fewer slave states in the north, so counting slaves and their population would not help many of the northern states gain representation. Secondly, the northern states felt that if the southern ones were allowed to count slaves as part of their population for representation, they should also be counted for taxation.
The solution was the three-fifths clause that was proposed by James Madison. Each slave would count as three-fifths of a person for both representation and taxation purposes. Even though slaves could not vote or enjoy any of the other rights of citizenship found in the Constitution, the three-fifths clause remained in place until slavery was finally outlawed, nearly 80 years after the signing of the Constitution.