[Uncle Sham]

Congress, the Supreme Court, AND the Executive branch have all proved that to secede is LEGAL by continuing to recognize West Virginia as a separate state from Virginia. Northern California should simply follow West Virginia’s example of forming their own state from within another.

[Bull Snipe]

If Virginia would have remained in the Union, West Virginia would not exist.

[rockrr]

West Virginia’s admission to the United States occurred with the consent of Congress.

[BroJoeK]

Uncle Sham: "Congress, the Supreme Court, AND the Executive branch have all proved that to secede is LEGAL by continuing to recognize West Virginia as a separate state from Virginia."

The US constitution requires approval by voters of the new state, by Congress and any "mother states" for one state to be created out of another.
For examples, when Maine was created out of Massachusetts and when West Virginia was created out of Virginia.

In each case the required approvals were granted.

For those who might claim that Virginia's legislature only approved "under duress", the fact remains that no later Virginia legislature ever withdrew its previous approval.

This procedure defines what our Founders intended by "mutual consent" for the union or disunion of political regions.