“…the perceived grievance must be very significant to wish to commit…”
The perceived grievance may be very significant but that does not make it more than perceived. It may not be real.
“It is the political reality.”
The political reality is that there will be no higher authority (as you admitted), no one else to judge, therefore your position (from post 1187 and elsewhere) “that states with equal authority cannot be judges of their own case” is erroneous as far as I can tell. There will be no one else in a position to judge. There will be no one in authority to tell them they can’t judge.
Your position that “any state can leave if the contract has been violated” is subject to the state’s ability to do so in the face of opposition.
“Practically speaking, if consent of all is required, secession is never going to happen.”
I don’t agree. If you’d said “improbable” or “not likely to happen” or something qualified like that I’d have been OK with it. But “never”? I can’t agree with that.
“The alternatives to my position are only these: chaotic revolution or enforced union.”
I don’t see how those are alternatives to your position “that states with equal authority cannot be judges of their own case”. There more like outcomes of states trying to be judges of their own case, but even that’s shaky. They don’t relate enough to your just stated position to be alternatives to it.
As to your position that “any state can leave if the contract has been violated”, I see chaotic revolution or enforced union more as possible outcomes than alternatives.
And I agree that “any state can leave if the contract has been violated”, putting an emphasis on “can” and subject to the State’s ability to do so in the face of opposition. If we replace “can” with “may” it might not make a difference.
Then, how?