Point of order. That particular "right" was seceded when they ratified the constitution. The Constitution to which they agreed, contains a clause that REQUIRES fugitive slaves to be returned to their masters.
A state cannot exercise a "right" they signed away. The Northern states were REQUIRED by the US constitution to return fugitive slaves, and they deliberately BROKE that constitutional law. Repeatedly.
More DL BS I see. Let's look at that clause in Section 2:
"No person held to service or labor 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 labor, but shall be delivered up on claim of the party to whom such service or labor may be due."
So what does that mean? If means that if a slave escapes and runs away to a free state that they are still a slave, regardless of what the laws of the state may say. Fair enough. If apprehended by the local authorities the slave must be extradited to his home state. Fair enough. But I don't see the part where it was the duty of the state to apprehend those slaves. Runaway slave laws were federal laws. It was up to the federal government to enforce, not the states. So your claim that the states broke constitutional law by refusing to apprehend runaways is nonsense. How can they break a law they were not required to enforce?