The value of federalism in our constitutional system is foreign to the thinking of leftists. With Trump in the White House it’s starting to make sense to them. California is the land of fruits, nuts and lotus eaters, and they want to be free to be who they are.
But secession is out of the question. One reason 19th century Americans lusted for California was as a gateway to trade with China and East Asia. The ports of San Diego and San Francisco were perfect, and still are. For reasons of national security, we can never lose them. We’re stuck with California.
For an analysis of why a breakup makes political sense for Democrats see this post in American Thinker.