Initially the North had proposed counting all the slaves

Initially the North had proposed counting all the slaves; the South insisted that slaves were not as productive as free workers, and suggested counting half the slaves. After proposed compromises of 2/3 and 3/4 failed to gain sufficient support, Congress finally settled on the three-fifths ratio proposed by James Madison. The proposed ratio was, however, a ready solution to the impasse that arose during the Constitutional Convention. In that situation, the alignment of the contending forces was the reverse of what had obtained under the Articles of Confederation. In amending the Articles, the North wanted slaves to count for more than the South did, because the objective was to determine taxes paid by the states to the federal government. In the Constitutional Convention, the more important issue was representation in Congress, so the South wanted slaves to count for more than the North did.
   On July 12th, 1787, the Three-fifths Compromise was enacted. Delegates to the Constitutional Convention in Philadelphia that year accepted a plan offered by James Madison determining a state’s representation in the U.S. House of Representatives. The issue of how to count slaves split the delegates into two orders. The northerners regarded slaves as property who should receive no representation. Southerners demanded that Blacks be counted with whites. The compromise clearly reflected the strength of the pro-slavery forces at the convention. The “Three-fifths Compromise” allowed a state to count three fifths of each Black person in determining political representation in the House. Rather than halting or slowing the importation of slaves in the south, slavery had been given a new life — a political life. Even when law stopped the importing of new slaves in 1808, the south continued to increase its overall political status and electoral votes by adding and breeding slaves illegally. The Three-fifths Compromise would not be challenged again until the Dred Scott case in 1856.