Yes, I am well aware of the Hartford Convention during the War of 1812. That is exactly how we know that the Founders regarded secession talk as treasonous. Later, when Vice President John C. Calhoun talked about secession, President Andrew Jackson, himself a Southern slaveowner, threatened to personally hang him.
Are you also well aware that our founding fathers seceded from Great Britain? Have you read any of Washington’s, Jefferson’s, Adams, or Henry’s words?