That's never going to happen. California would never willingly allow positive revenue counties to leave.
I am wondering if there is any practical way to trigger that earthquake they have been bitching about forever. You know, the one that is supposed to cause CA to "fall" into the Pacific. Because that's one way out. But you'd still have to build the big fence first to keep any refugees from getting out. A big electric fence. With a moat. An alligator filled moat. Plus towers with sharpshooters. And maybe some minefields with video surveillance that can go up on a pay-per-view channel. Otherwise they will just get out and infect other states.
Or round them all up and send them to Canada. That would be okay. If Hawaii was big enough they could all be shipped there.
If only there was some way to trick them all into emigrating to Venus like in
C.M. Kornbluth's "The Marching Morons." At some point down the line we have to give some serious consideration into slowing down or halting their rate of breeding. The poisoning of our gene pool with below average intelligence genetic material is a very big deal. Perhaps some kind of a sterilization agent can be introduced into the CA drinking water. Or better yet, come up with a sterilization agent that can be introduced into grapes and dairy products so that the cheese and wine demographic can be directly targeted.
This project can certainly be tackled by Texas A&M University and they can test it on Austin to see if it works on a small scale before going after the whole state of CA.