Andrew Jackson showed that secession was unconstitutional as clearly as any.
There is nothing in the Constitution claiming it to be a contract. This is just another misunderstanding of the document concocted to defend such indefensible acts as destruction of the Union.
As I said even IF it were a contract secession would be illegal. Courts are were contact disputes are settled not insurrection.
Insurrection disguised as "secession" is still insurrection and the Founders placed the ability to respond to insurrection firmly in the document.
One of your problems is trying to pretend that insurrection was something else then demanding proof that that something else was forbidden. Sneaky but only with the stupid would it work.
Slavery was the ONLY reason the RAT lead insurrection occurred so one must look at the context of the legal "argument" which wasn't an argument either just insurrection.
laughing AT you!
free dixie,sw