And if thy right eye offend thee, pluck it out, and cast it from thee: for it is profitable for thee that one of thy members should perish, and not that thy whole body should be cast into hell.
Litany of secession:
If the federal government causes you to sin against God then secede from it, cut it off like a cancerous limb; cast it from thee because it is far better to live in a smaller, free republic of God fearing states than perish in the hellfire of centralized federal tyranny. Whatever hardship may come secede just the same for it is profitable for a group of states to restore a Free Republic than let the entire nation cast your state into hell.
To my mind, the northern US states had a better argument for secession than the southern states. The northern states were being denied due process for their citizens by the southern dominated US government. Further, they were being denied the authority to ban slavery on their own territory.
Still, they did not pretend to secession.
Slavery was indeed the kind of sin that would have justified secession, on the part of those who were opposed to the kidnapping, rape, and torture that were routinely used by the slave power. Justifying secession based on the demand that pretended rights to rape, torture, and kidnapping, not so much.