[x]

Secession means complete and total political dis-unification. States leaving the union would no longer be a part of the federal union, and therefore not subject to any claims by that now 'foreign' government.

Because you say so? Because it feels good?

Any kind of dissolution of the union is going to involve cooperation, compromise, and give and take between various authorities.

Shortsightedness and overreaching did a lot to doom earlier attempts at disunion, and would derail any future effort.

[NTHockey]

It seems to me that there are three options available:
1. Accept the status quo & eventual loss of all freedom;
2. Peaceful secession - mass relocations & parsing the Treasury; or
3. All out revolution with all the attendant horrors.

Option 1 and 3 are non-starters. One is slavery; the other treason.
Option 2 is a viable solution; provided there is cooperation, something in very short supply in government.

[Windflier]

Any kind of dissolution of the union is going to involve cooperation, compromise, and give and take between various authorities.

Sure there will, but that's another subject entirely.

The fact is, once a portion of a country has broken away from its former political union, it becomes a sovereign nation - not under the control of that political union it has left.

The remaining portion of that political union has no authority or rights whatsoever over the new nation. Whatever treaties, payments, etcetera that need to be worked out, will be done at the bargaining table as equals.