It's absurd because Californian's aren't really a nationality in the way the British or French are. People talk about red states and blue states, but that's just the mix of rural/surburban/urban people in the state. Rural Californians are much more in common with rural Texans than with Los Angelenos.

There is more cultural variance within just Spain than the entirety of the USA. We truly are one people.

Ironically, calling for a USA that is just an common defense alliance with open trade borders is pretty much what conservatives want. They'll be happy to cut taxes, and let California experiment with what it wants.