Simple solution. Trump signs Executive Order decertifying all Mexifornia elections.
I’ll see your state and raise you a nation.
I don’t think that EO would be constitutional. States have a lot of latitude in how they handle elections. It needs to challenged in court on civil rights grounds that its an invitation for fraud. Its integrity is impossible to maintain and thus will disenfranchise legitimate California citizens. That law suit needs to start now and go up to USSC if necessary.