The counties in question to remain in the Union should gather, declare themselves to be California, and purge the offending secessionists.
That is kick out LA and San Francisco etc. A congress of 3 representatives from the counties to remain can meet, write the purge declaration and vote on it.
It can be called the Declaration of Purgation.
And the secessionist counties will become an independent nation but protectorates of the U.S.A. Remember: the Monroe Doctrine prevents their coming under foreign domination, and this means Canada, which is part of the British Commonwealth, although they might be allowed to become, once again, part of Mexico, which would be karmically just.
They need protection anyway. They have shown that they are unable to govern themselves--or participate in U.S. government.