If you feel that Northern states were simply exercising their state sovereignty by ignoring Article IV Section 2 of the Constitution, then you shouldn't be surprised that other sovereign states said to hell with this, if you're not keeping the Constitutional bargain you made, we're leaving.
That is what the Philadelphia Public Ledger article I posted warned about.
FYI, Massachusetts' personal liberty laws included the following:
Any person who shall act as counsel or attorney for any claimant of any alleged fugitive from service or labor, under or by virtue of the acts of congress mentioned in the ninth section of this act, shall be deemed to have resigned any commission from the Commonwealth that he may possess, and he shall be thereafter incapacitated from appearing as counsel or attorney in the courts of this Commonwealth...
It is no wonder that many Massachusetts attorneys and judges thought the law was unconstitutional.
How were they ignoring Article IV, Section 2. A fugitive today, or a white fugitive then, had protection of habeas corpus, the right to an extradition hearing, the right to legal counsel, the right to fight that extradition. Are any of those violations of Article IV, Section 2? Of course not, but when the Northern states tried to grant those same rights to runaway slaves the Supreme Court struck them down. And when the Northern states refused to assist in the enforcement of the fugitive slave laws, as the Supreme Court ruled they were not required to, then the southern states claim it as a lame excuse for rebellion.
FYI, Massachusetts' personal liberty laws included the following:
And? Are you saying that the commonwealth did not have the power to regulate their attorneys?
It is no wonder that many Massachusetts attorneys and judges thought the law was unconstitutional.
The unconstitutionality lay in the fact that such laws had been struck down by the Taney court before, and would no doubt be struck down again. Every law passed in recent times severely limiting a woman's access to abortion has been struck down, but that doesn't stop states from trying.