NE states will never agree to the land and oil rich states leaving and taking their assets with them.
That may be, or may not be, depending on the terms, but the legal requirement is for significant agreement, by enough to get 3/4 of the states for an amendment, or 2/3rds to get a treaty ratified by the Senate.
Simi Valley attempted so separate from the city of Los Angeles a few years ago. The ballot measure agreed that Simi Valley would pay $680 million to Los Angeles in the first few years after the separation.
It was voted down, but was close.
That may show the way to a deal, or it may show that the people considering secession just don’t want it bad enough.
If a state were to arm itself with nuclear weapons and then tell the people of the cities of Boston and New York City that they're the first order of business in any war to prevent secession...then I expect the liberal statists to cave instantly.
Yes, the ticks will hold onto their hosts as long as they can.