Totally true. I work in Silicon Valley but have a weekend house in the Sierras. Everyone up there is conservative. If California voted to secede, counties like that one would leave California to stay in the US. And given that’s where all the water comes from (for Northern Cal at least)......
Should that come to pass, do not rejoin another state in the US, but become your own state, say, Northern California, not yet part of the US, and keep the dam libturds out, ship them out, whatever,..., set up your own laws that align with the US Constitution, then rejoin the US.
Most of the drinking water for Southern California comes from the Colorado River Aqueduct. If California attempt to succeed it's agricultural industry is going to be hard hit as the water will be cut off and Arizona will become the new Imperial Vally.
Southern California gets its water supply from eight other states which I don't think will be willing to share the water.