The three-fifths rule of the Constitution treated slaves as three fifths of a person for purposes of representation and direct taxation. This provision is puzzling in many ways (above and beyond its connection with slavery). One common way it has confused people is that people often regard the Clause as problematic because it did not treat slaves as 5/5 of a person. But if the Clause had treated slaves in that way, it would not have harmed but benefited slave states, since slave states would have enjoyed more representation in the Congress and the electoral college.
But I am puzzled by another aspect of the Clause. What made people believe it was an appropriate compromise between slave and free states? Representation and direct taxation could have been based on the number of persons in the state or on property. The convention chose not to base it on property but on the number of persons. But slaves were treated as property. Thus, representation and direct taxation should be based entirely on the number of free persons, with slaves counting for 0/5. As Elbridge Gerry said at the Convention, why “should the blacks, who were property in the South, be in the rule of representation more than the cattle & horses of the North?” This is harsh language as judged by our modern sensibilities, but it captures the point.
Of course, as things turned out, Gerry’s argument, if accepted, would have benefited the free states, but that is not my point. My question is why it was regarded as a legitimate compromise.
It is true that the compromise had already been discussed for requisitions under the Articles of Confederation. And it might or might not have made sense there. But for the Constitution itself, it just does not seem to make sense.