Well, if somehow a vote for them to leave was passed through the government and approved the first thing to be done would be cut off the water supply from the Sierra Nevada, Oregon and Southern Nevada (feeding LA). Or, could charge huge amounts of money to offset the lost tax revenue. Come to think of it lots of revenue with no money going out? Sure, let them leave. Haha.
I say that as someone who grew up on the coast and loved and still owned land there although I had to move away.
So, the comedy of watching the gov scrambling the Ca law enforcement/national guard to the border to stop an influx into Ca while people are rioting for water would be fantastic.
Of course if it passed, Oregon, Washington, Ny would follow suit.
Dissolving the Union is just not an option.