Madison explicitly wrote Hamilton during that NY ratification convention and said that once in the Union always in the Union. He did not believe in a right to secede.
But since there was NO “intolerable” oppression, other than that visited upon slaves by the whips and chains of the slavers, so the RAT Rebellion was completely unjustified and would never have been supported by Madison. Southern states were in no way oppressed by the federal government.
Madison explicitly wrote Hamilton during that NY ratification convention and said that once in the Union always in the Union.
Madison was also a weak-minded and easily swayed vacillator on almost all constitutional matters involving state-federal relations. He eventually settled at the end of his life into a self-contradictory embrace of duel sovereignty in name while denying the same in practice while also denying that he was denying the same in practice, or the constitutional equivalent of trying to have his cake and eat it too. His career long inconsistency on the subject is so fraught with holes that it is difficult to uphold him as an authority.