Those are both interesting opinion pieces but irrelevant.
If we accept the idea that the Constitution is a compact between equals, then it stands to reason that no one state has any powers denied another state. Likewise it would also stand to reason that the Constitution protects all states equally. But to believe that states may leave at will, without the consent of all the impacted parties, is to believe that only the seceding states have rights that are to be respected and that only the seceding states have any protections. They are free to take any action, regardless of how it may harm the remaining states, just by leaving and there is nothing that those states can do to prevent it. I doubt any of the Founding Fathers supported such a notion.
The south, knowing that they had no legal right to unilaterally secede, did so anyway. This was the source of a disagreement with the sitting president. Unfortunately although he said it was illegal he also claimed that he was powerless to stop it.
Eventually this disagreement took on the sharp edge of open hostilities. A war was waged and the south lost. An after effect of the civil War was a Supreme Court ruling that renders these to op-ed pieces irrelevant, That ruling is Texas v. White and still stands.
Secession - as practiced by the slavers in 1861 - is illegal.
Your post is an opinion piece. It too is irrelevant, accepted only by the like minded, who are wrong.
Secession was clearly both legal and constitutional. Those who denied that were driven by their own agendas, ignoring both facts and history. There's was a disservice to liberty and an affront to the founding documents. The shame of the unlawful war and mass murder they brought forth is theirs to bear for all eternity.
I will give you the opportunity to have the last word so the tedious anti-liberty argument will have it's champion.
Good day.