I does look like Dred Scott became a resident of Illinois, having lived there almost three years before eventually moving back to Missouri. That might not be the game changer, but I think due process is (as I said, I think this Dred Scott case is fascinating).
Until the Reconstruction Amendments, slavery was a states’ issue, not a constitutional or federal issue. So what’s left IMO, is whether Dred Scott’s owner was allowed due process in the depriving of his property (Scott). It certainly appears that there was due process because the Missouri Supreme Court reviewed the case.
Although I think there were grounds to call the Missouri Compromise unconstitutional, Illinois was a free state regardless of the Missouri Compromise so I see the Missouri Compromise as irrelevant in this case. The federal courts should not have taken the case as there was no federal question unless there was diversity (don’t know). But even if there was diversity, I don’t see what authority or constitutional basis Taney had to reverse the Missouri Supreme Court’s ruling.
So I guess I’ve changed my mind back to saying Dred Scott was wrongly decided because of due process. Because Dred Scott’s case was properly heard in the Missouri Supreme Court, Dred Scott was wrongly decided by SCOTUS and Taney because there was no constitutional ground to reverse the Missouri Supreme Court.
That being the case, the South DID have a constitutional grievance against the North. However, I don’t think a single legal grievance constitutes justification for secession (there were 27 specific legal grievances listed in the Declaration of Independence).
Correction. My last paragraph should have read...
Dred Scott represents the North making an unconstitutional decision in favor of the South. The South could hardly complain about that. The Missouri Compromise had been repealed and later declared unconstitutional (kinda like sentencing someone to be hung until dead and then sentencing him to be shot). The Kansas Nebraska Act favored the South as well. so it appears the South was short on constitutional grievances against the North which were necessary IMO to justify secession. (There were 27 specific legal grievances listed in the Declaration of Independence from England’s rule.)
The Federal issue at stake was Article IV section 2. Your argument that "Illinois was a free state regardless of the Missouri Compromise " is tantamount to putting conditions on Article IV section 2 which are not in the text of the law.
The agreement of the founders and the signatory states was to clearly allow slavery consistent with the laws of the member states which had slavery laws. Changing the rules so that they can no longer exercise the same rights as they had when the agreement was signed, represents a breach of contract.