Feel free to look them all up.
He is only ONE of the founding fathers anyhow.
But the one single one who was most responsible for creating the Constitution. What you're actually saying is "What the hell did he know?"
But as LG has pointed out, obviously the issue didn’t seem important enough to prohibit, and you know why?
Because neither Madison or any of the other founders thought anyone would be dumb enough to believe unilateral secession was legal?
Because the states would have never ratified the Constitution if secession had been prohibited.
And for the umpteenth time, secession isn't prohibited. Unilateral secession is.
OK. let me change that to “the states would not have ratified the Constitution if UNILATERAL secession had been prohibited.”
John C. Calhoun, one of the greatest and most brilliant statesman that ever lived believed in unilateral secession.