It sounds like the non-urban areas want to be separated from the southern urban areas, because of the way they are governed.
I understand their rationale. Don’t know how this works...they make it sound similar to the way West Virginia was formed as an independent state.
If the Constitution supports this type of activity, I can go with it.
It doesn't. The Constitution expressly forbids creating new states from already existing state's land without the consent of that state's government.
Meaning the California State Assembly would have to vote to approve this. I'm sure that's going to happen.
I don’t think you’d need to change the US Constitution. California would need to approve it using whatever means is applicable and then the Congress would need to approve it.
The Constitution says only Congress has the power to change the boundaries of existing states.