The North could exist without the Southern produced tariff revenue, but it would mean a lot of money leaving the pockets of wealthy powerful men in the North who liked having that money coming into their pockets.
They weren't going to allow the South to walk away.
The North would have just been cut off from it's addiction to Southern produced money, and like a drug addict, they reacted violently, blamed others, and took out their rage on the victim.
At the root of every conflict is greed and “love of money”.
The South, while not on the moral high ground with regards to slavery - had every right to succeed.
It’s a tragedy that over 500,000 of some of our best were destroyed in a conflict that could have been avoided.