And later in the same letter from James Madison, "Father of the Constitution", "The characteristic distinction between free Governments and Governments not free is, that the former are founded on compact, not between the Government and those for whom it acts, but between the parties creating the Government. Each of those being equal, neither can have more rights to say that the compact has been violated and dissolved, than every other has to deny the fact, and to insist on the execution of the bargains."
Total vindication of the southern position. At the time of the Second American Revolution, the North was not insisting “on the execution of the bargains” - except, perhaps, where it was in their economic and political best interests.
Where the bargains were not to their liking - the Fugitive Slave Clause, to cite an example, northern political and business leadership were openly repudiating and violating the covenants of the Constitution. In the case of John Brown, wealthy northerners funded his murder raids while northern politicians set up sanctuaries for him and his terrorist organization. That was not something that could continue.