the governor of Ohio refuse to obey the requisition of the governor of Tennessee for a Negro thief...
Did Tennessee sue in federal court regarding this?
and is it probable that Lincoln will regard his oath any more than they have shown themselves to regard it?
Ah, here is the rub. The South's justification is anticipatory constitutional violations. That is not valid justification for secession according to the D of I. The South anticipated all kinds of "probabilities", but the D of I template is "a long train abuses and usurpations" which in this case would be multiple cases of unconstitutional federal acts pleaded for in federal court but unredressed.
The only specific grievance mentioned here was between two states, not with the feds. If Tennessee failed to bring the matter before a federal court, then they failed to give the feds a chance to right a constitutional wrong. This isn't a "long train" of wrongs by the feds. So far I haven't seen any unconstitutional acts by the feds.
It would appear the South falls way short of valid secession.
Not just fugitive slaves - fugitives responsible for the John Brown murder raid. Southern states were simply not going to allow northern states to set up sanctuaries for terrorist organizations to stage murder raids on sister states.
Daniel Webster was right: A bargain cannot be broken on one side and still bind the other side.
Even today, terrorist activities allowed or encouraged by sanctuary states will prompt adverse reactions. Consider this Wikipedia entry:
“In 2001, U.S. President George W. Bush demanded that the Taliban hand over Osama bin Laden and expel al-Qaeda; bin Laden had already been wanted by the United Nations since 1999. The Taliban declined to extradite him unless given evidence of his involvement in the September 11 attacks[49] and also declined demands to extradite others on the same grounds. The request for evidence was dismissed by the U.S. as a delaying tactic, and on 7 October 2001 it launched Operation Enduring Freedom with the United Kingdom.”