They can take whatever parts vote to go.
The rest stays.
Good luck running a country with little to export other than crappy movies.
The problem is that California has literally been invaded by millions of Mexicans and South Americans. Over 40% of people residing in California speak a language other than English at home and most currently have no desire to assimilate into our society. If one invalidated the millions of votes from the illegal invaders registered when they were given their drivers licenses then the situation looks quite different electorally. The Democrats made it easy for them to vote illegally and actually encouraged them to do it. This sanctuary city crap is to protect all the illegal Democrat votes. At this point Latinos now outnumber Whites in California.
http://www.latimes.com/local/california/
As you allude, even as it is currently however, 2/3rds to 3/4s of the land mass are still in conservative areas. It is the population centers around Los Angeles and San Francisco that are the biggest Democrat areas.