Which has what to do, exactly with the Madison's statements concerning the subject at hand?
Applying a like view of the subject to the case of the U. S. it results, that the compact being among individuals as imbodied into States, no State can at pleasure release itself therefrom, and set up for itself. The compact can only be dissolved by the consent of the other parties, or by usurpations or abuses of power justly having that effect.
James Madison to Nicholas P. Trist, 15 Feb. 1830
Since you're asking that question, I'll just assume you don't understand the word, "compact" in the text you're repeatedly citing, or in the context of the Republic of West Florida.