Not to pick nits, but I assume Steve Benen knows that the problem with the Federal ratio (e.g., “3/5 compromise”) wasn’t that it defined slaves as “three-fifths of a person” in any moral sense, but that it provided slaveholding states with additional representation in both the US House as well as in the Electoral College, thus assuring them of disproportionate influence in national affairs for generations longer than they deserved. Nor was the 3/5 compromise solely to blame for the South’s undue advantage. When Northern population growth overcame (to some degree at least) the malapportionment in the House by the 1840s, the effects of the Connecticut compromise extended the life of the slave interests even further, with the man-stealers and tyrants clinging to their artificial parity in the Senate. Indeed, if Elena Kagan would add “the United States Senate” to her list of “defective” innovations in the US Constitution, I’ll happily offer her my utterly meaningless endorsement.
That being said, it’s always worth remembering that Southern representatives at the Constitutional Convention would actually have preferred to classify slaves as “full” persons for the purposes of apportioning federal representation. Of course, these same delegates would have preferred to classify slaves as property for the purposes of assessing direct taxes on the states, since those taxes would be based on population figures. Though I understand the urge to see the 3/5 ratio as capturing the moral essence of the founders’ disposition toward race and citizenship — and to the degree that it helped preserve while political supremacy, there’s something to that claim — the compromise really didn’t mean what it’s conventionally taken to mean.
(Bonus nit-picking: It was the 14th, not the 13th Amendment, that kicked the legs out from the 3/5 compromise by apportioning representation according to the “whole number” of persons in each state.)