When the Convention took up the Committee’s report the next day, General Pinckney immediately moved that the span during which the slave trade would be protected should be prolonged: from the year 1800 to 1808. Madison jumped to his feet to object: “Twenty years will produce all the mischief that can be apprehended from the liberty to import slaves. So long a term will be more dishonorable to the American character than to say nothing about it in the Constitution.” Since General Pinckney and James Madison had both been on the committee that drafted this compromise, it is very likely that this exchange was a reprise of an earlier battle that had already been fought in committee, with the South Carolinian evidently believing that he had been on the losing side. However, if it was true that he had already lost in committee, Pinckney’s appeal was now directed to an assemblage that was more disposed to appease him. Madison’s objection was the only one voiced, and the extension passed, 7-to-4. There is a palpable sense in the exchanges from this day forward that the delegates were now eager to contain and resolve this late-blooming explosion as quickly and tidily as possible; they had no wish to allow a few hot tempers to overthrow an entire summer’s labors, even over such a difficult and volatile issue as slavery. The standoff over the slave trade would be the Convention’s last major crisis.
Finally, and with very little further debate, the 20-year compromise on the slave trade was passed by the same division of votes that had extended the years that such a trade would be protected (New Jersey, Pennsylvania, Delaware, and Virginia being the only states to vote against it). The delegates then proceeded to debate the related clause about placing duties on the imported slaves. Interestingly, those who were unified in their opposition to the slave trade were divided on this question. Sherman and Madison did not want any duties attached to the importations, because it had the effect of “acknowledging men to be property,” and they “thought it wrong to admit in the Constitution the idea that there could be property in men.” Others, however, argued that exempting slave importers from paying any duties at all would be the practical equivalent of granting them a bounty on their trade, because they would be the only traders who were exempt from paying taxes. For those who were opposed to the slave trade, the choice lay between a distasteful logical implication or an offensive practical result. The delegates from the Deep South only wanted to be assured that Congress could not levy such a high duty that it would be tantamount to a prohibition on the imports. The delegates ultimately agreed that a duty could be imposed “not exceeding ten dollars for each person.”
Charles Pinckney tried to dismantle the part of the report dealing with Navigation Acts, moving instead that all commercial acts, whether international or interstate, should require a two-thirds majority. This change would have seriously undermined the new government’s authority over commerce. But his two colleagues from South Carolina quashed that attempt; after all, a deal is a deal, and a Southerner does not try to back out of a gentleman’s agreement. The provision that required a two-thirds majority for navigation acts was then struck from the draft without further dissent, and the bargain between the Deep South and the New England States had been consummated. The final touch was added on September 10, when South Carolina insisted that the twenty-year compromise must be safe from the amendment process. If their experience in the Convention had taught them anything, it was that the slave trade was so unpopular among the other states that its opponents could easily muster the three-fourths majority necessary to pass an amendment repealing the twenty-year allowance for the trade. The states voted, 9-to-1, to safeguard that provision from the threat of amendment. Even many of those who had been opposed to the original compromise showed a willingness to abide by the deal once it had been struck.