Even that won't happen..... there is no legal route for succession from the US by state, county, city or any other legally-recognized incorporated territory chunk, the only way it can happen is through successful force-of-arms, which nobody at current has the means to do, on either side of the debate.
Everyone fretting about a Civil War, or wanting one, utterly fails to reasonably present a scenario where it happens and is successful (i.e.- no Federal force is used, or is used unsuccesfully, to quell it)
Nobody can even demonstrate what groups of people (Specifically, I want an actual named group, not just "Revolutionaries" ) would take up arms and what specific objectives they'd try to seize.
Until you can cite both of those for me, there's no point at even carrying the "Civil War" discussion anywhere.