But, as ditto said, Tanney's decision went far beyond what the Constitution recognized & authorized.
In effect, Tanney made slavery lawful in every state & territory, regardless of states' rights or Congress' authority over territories, and Tanney outlawed citizenship for African-Americans, regardless of their status, free or slave.
No Founder intended such laws, and everyone north of the Mason-Dixon line understood that, as well as many in the South.
Let us see if we can at least agree on what the Constitution itself says.
No Person held to Service or Labour in one State, under the Laws thereof, escaping into another, shall, in Consequence of any Law or Regulation therein, be discharged from such Service or Labour, but shall be delivered up on Claim of the Party to whom such Service or Labour may be due.
I understand this to mean that no state can pass a law depriving a man "from such service or labour" as he is legally due.
Meaning that going to another state will not free a slave from the labor he owes to whomever has the legal right to his labor.
Do you understand this to mean something different?
There I think he went too far. That assertion is a non-sequitur. There were free Blacks who participated in and fought for the Revolution. Tanney is right that the Declaration of Independence was never comprehended to refer to slaves, but this cannot be argued in regards to black men who were free and living in the country at the time, though their numbers be relatively small compared to the rest.