I agree that slaves were not counted as citizens prior to the abolition of slavery. But were they persons? The constitution counted them as 3/5ths of a person for the purpose of taxation and for reapportionment, prior to the ratification of the 13th, 14th, and 15th amendments.
Sure, they were considered persons by the Constitution, but maybe not by some indiviuduals (north or south), but not citizens. Recall that the south demanded the 3/5ths rule to insure they held a significant amount of political power, elsewise they would not agree to the constitution, let alone ratifiy it. 60% of the slaves/Indians not taxed added population towards seats in the US House, to the advantage of the Southern states, those same persons had no vote or voice as to how they were represented.
Recall, that Dread Scott resulted in the decision that we are discussing- Dread Scott, as a slave born in one state, could not claim freedom/citizenship in any other state, since as by condition of birth he was constitutioanlly recognized as such, and that the Fugivtive Slave Act required the return of such persons back to their owners-in all states, slave or free; so there was no method of becoming free except at the hand of the lawful slave owner... Perverse, huh?. Folks will argue that point, but that is what the SCOTUS determined based on the constitutional wording and the politics of the day. The Court treated the issue as it was written (although it was an immoral and inhuman fact), which is a far cry from we all too often see today!
No one ever said the document was perfect; and the intent of the issue in question was to form a union. Jefferson and Adams and Franklin and many others hoped and expected the slavery issue to resolve itself based on economics, population and not war/disolution of the union. They sacrificed the issue of slavery to form a “more perfect” union, not a “perfect” union.
Only socialists/communists dare to declare themselves capable of that lofty, heavenly goal (sarc)-by making evryone a slave IMO...
If you wish to learn more about these topics- go to cato.org and then to the cato university home study courses-download to CD and get background from Locke, Smith, the US Constitution and BOR/Amendments to Mieses and everything of note in between. While a decidedly libertarian site, I find almost nothing in the context of historical fact to argue with in reference to the founding ideology of this nation, and our way of life.