Ownership of slaves was a practice that the colonists brought with them when they journeyed to the New World. Shortly after the revolution most northern states and even some large planters of the south freed their slaves. The issue of slaves freedom resurfaced again during the Constitutional Convention and this time it threatened to end negotiations.
Shortly after the revolution the attitude toward slavery in the northern colonies began to shift. They began to see the practice as inhumane and discriminatory. Also, most of the northern colonies did not have a solid economic argument for continuing to keep slaves. In the south however, the colonies were primarily large plantations where the planters relied on slaves to work the crops. The number of slaves a planter owned had a direct correlation to the amount of revenue he could generate.
During the Constitutional Convention, the northern and southern states argued vehemently for their side of the issue. One major point that the northerners did not agree with was the three-fifths rule for slave representation. They felt it afforded the southern colonies additional power within the government. The southern colonies argued that to abolish slavery would cause them to suffer a huge economic setback and directly affect their representation in the government.
It is speculated that the northern colonies may have been too forceful in their arguments against slavery. This caused the southern colonies to threaten to abandon the convention. Their leaving would mean that the hopes of forming a national government would be demolished. After the realization that the convention could come to a screeching halt, the delegates began to work toward a compromise.
Toward the end of the negotiations, the southern colonies expressed a concern about additional taxes on the export of rice and tobacco. They demanded laws concerning trade require a two-thirds vote in the legislature in order