Mr. George Mason said, that gentlemen might think themselves secured by the restriction in the fourth clause, capitation or other direct tax should he laid but in proportion to the census before directed to be taken. But that when maturely considered it would be found to be no security whatsoever. It was nothing but a direct assertion, or mere confirmation of the clause which fixed the ratio of taxes and representation. It only meant that the quantum to be raised of each State should be in proportion to their numbers in the manner therein directed. But the general government was not precluded from laying the proportion of any particular State on any one species of property they might think proper. For instance, if five hundred thousand dollars were to be raised, they might lay the whole of the proportion of Southern States on the blacks, or any one species of property: so that by laying taxes too heavily on slaves, they might totally annihilate that kind of property. No real security could arise from the clause which provides, that persons held to labor in one State, escaping into another, shall be delivered up. This only meant, that runaway slaves should not be protected in other States. As to the exclusion of ex post facto laws, it could not be said to create any security in this case. For laying a tax on slaves would not be ex post facto.
Mr. Madison replied, that even the Southern States, who were most affected, were perfectly satisfied with this provision, and dreaded no danger to the property they now hold. It appeared to him, that the general government would not intermeddle with that property for twenty years, but to lay a tax on every slave imported, not exceeding ten dollars; and that after the expiration of that period they might prohibit the traffic altogether. The census in the constitution was intended to introduce equality in the burdens to be laid on the community. No gentleman objected to laying duties, imposts, and excises, uniformly. But uniformity of taxes would be subversive to the principles of equality: for that it was not possible to select any article which would be easy for one State, but what would be heavy for another. That the proportion of each State being ascertained, it would be raised by the general government in the most convenient manner for the people, and not by the selection of any one particular object. That there must be some decree of confidence put in agents, or else we must reject a state of civil society altogether. Another great security to this property, which he mentioned, was, that five States were greatly interested in that species of property, and there were other States which had some slaves, and had made no attempt, or taken any step to take them from the people. There were a few slaves in New York, New Jersey and Connecticut: these States could, probably, oppose any attempts to annihilate this species of property. He concluded, by observing, that he would be glad to leave the decision of this to the committee.