If California were to secede it would end up as another Venezuela or any other Latin or Central American country. Lots of economic potential because of its proximity to valuable natural resources, but run into the ground economically by idiot leftists in charge of the government.
Most liberals talk the talk but won’t walk the walk when it comes to living the regulated lifestyle of pure liberalism, so they flee to other states.
If California secedes then Trump will need to wall it off Mexican border style. East German border style would be even better.