Southern delegates to the Constitutional Convention (especially those from South Carolina and Georgia) brought this spirit of liberty with them to Philadelphia. They insisted that any federal government established by a new constitution must respect and protect their property rights. The problem, of course, was that those delegates viewed slaves as a type of property, so they wanted assurances that the new constitution would not threaten the institution of slavery. But many of the delegates were opposed to slavery, including some slaveholders from Virginia, and a few roundly condemned the “peculiar institution” on the floor of the Philadelphia Convention.

None of the antislavery delegates called for a condemnation or prohibition of slavery to be written into the Constitution. This would have been a futile, utopian gesture, one that would have caused the Deep South bloc to desert the Convention and eliminate any chance of those states joining the Union. After Gouverneur Morris, an antislavery delegate from Pennsylvania, said in a speech that slavery is “a nefarious institution—It was the curse of heaven on the States where it prevailed,” southern delegates refocused delegates on the primary purpose of the Convention. They pointed out that the purpose of a new constitution was to forge a political union, not a moral union, among the states. Moral considerations should be left to the individual states, not to the national government.

In his defense of the slave trade, which even some proslavery advocates found repulsive, John Rutledge (South Carolina) stated: “Religion & Humanity had nothing to do with this question. Interest alone is the governing principle with Nations.” Charles Pickney (South Carolina) backed up Rutledge by insisting that South Carolina would never accept vesting Congress with the power of “meddling with the importation of negroes.” Rutledge warned that “the true question at present is whether the Southern States shall or shall not be parties to the Union.” Historian William M. Wieck was exactly right when he wrote (The Sources of Antislavery Constitutionalism in America, 1760–1848, p. 73): “[F]or the framers, the highest good was national union. For this they sacrificed all other considerations, including the well‐​being of black Americans.”

The need to compromise on slavery for the sake of a union, even at the expense of violating human rights, was clearly understood by all sides. Consider the following remarks by one of the Convention’s most strident opponents of slavery—the eminent legal philosopher James Wilson—as reported in James Madison’s Notes of Debates in the Federal Convention of 1797. In debates over the three‐​fifths rule (or “federal ratio”), according to which slaves would be counted as three‐​fifths of a person when computing the number of representatives allotted to a state in the House of Representatives, Wilson’s remarks are recounted as follows: