I am terribly sorry, my friend, but you are operating under a completely mistaken understanding of the American concept of delegation of powers. The powers granted to the Federal government are granted to them not by the Constitution, which is a non-living instrument, similar to a treaty; but, by the States, which are the sovereign signatories TO that treaty.
You will find NO, and I cannot stress this enough, contemporary resources, books, newspaper articles, or other material from the timeframe surrounding the ratification of the Constitution, that would suggest ANYTHING similar to the position you are taking, my friend, and I urge you to go back and look at the DIRECT historical record if you don't believe me. Original sources, original sources, original sources!
The States agreed, under the Articles of Confederation and the Acts of the united States in Congress Assembled (hereafter, the Confederacy Congress), that the matter of borders should be something that should be negotiated by the States in joint Congress. The reason for this is not because the Constitution is somehow supreme, but because the States were in disagreement over where their borders began and where they ended (due to the vague way in which the Colonies boundaries were laid out by ROYAL Charter). Remember - These original borders were accepted by the Confederacy Congress, and were modified due to negotiations between the Sovereign states which participated in said Congress.
On the topic of the admission of States, this is once again not some area in which the Constititution is somehow supreme, but this is a method by which the States, who retained their Sovereignty but DELEGATED CERTAIN POWERS to the Federal government, decided to JOINTLY determine which areas should be admitted to the Confederacy (and later, the Federal union) on equal terms as them.
You're a bit quick to use that term. Please stop.
You will find NO, and I cannot stress this enough, contemporary resources, books, newspaper articles, or other material from the timeframe surrounding the ratification of the Constitution, that would suggest ANYTHING similar to the position you are taking, my friend, and I urge you to go back and look at the DIRECT historical record if you don't believe me. Original sources, original sources, original sources!
OK, how about some sources to support your position? How about the quote from the founding father that says a state may, for any reason, abrogate responsibility for obligations built up by the nation as a whole while that state was a part of it? Please tell me what founder agrees that any state may seize common property at will and without compensation. Point out what federalist paper supports the idea that Maryland or Ohio can be cut off from access to the sea by another state, regardless of the impact this action has on the interest and economic well-being of that state. Please show me where any one supports any of those concepts and I'll agree that they support your concept of secession at will, for any reason or no reason at all, regardless of the consequences.
Seceding states are not the only sovereign one, and are not the only ones with constitutional rights. The remaining states are impacted by secession, and deserve a say in the matter. You may not agree with that, but it is clear in the Constitution that the founders did not feel that once Congress admitted them that the states should have sole say over changes in their status. Splitting or combining with another state or changing borders all could have an impact, positive or negative, on the other states and Congress believed that the other states should at least have a say in the matter before the action took place. That is why Congressional approval is needed. And when a state decides to walk away from the national debt or treaty obligations, when they appropriate commonly held property, or before they cut off access to the Mississippi from the rest of the United States then shouldn't the rest of the states have a say?
The reason for this is not because the Constitution is somehow supreme...
But the Constitution IS supreme, as Article VI, Clause 2 clearly states.