So, you not only justify slavery in the South, you also deny the constitutuional right of Northern states to abolish slavery within their own boundaries?
What we know for certain is that Northern states began abolishing slavery in 1777, and by the time of the Constitutional Convention in 1787, all but New York and New Jersey had passed such laws.
So, there's no suggestion from our Founders that slavery could not be abolished by states which didn't want it.
Indeed, all indications are the opposite -- slavery was in those days expected to be abolished, gradually, lawfully, even in the South.
That's what abolishing international imports of new slaves was all about.
Fugitive Slave provisions were understood to mean just that: when runaway slaves were captured, they must be returned to their "owners" -- it certainly did not mean that Southern tobacco farmers could bring their slaves north to grow tobacco in, say, Pennsylvania.
So, Tanney and now you are providing a Constitutional interpretation which was and is firmly rejected by scholars, historians and absolutely rejected by Northern voters in 1860.
I'm asking you if that is what it means. Unless my English is faulty, I read it as a rendering null any state law designed to free a slave.
If you do not think that is what it means, why don't you explain to me what you think it means?