In 1860 the split was regional. 90%+ of (white) people in most of the southern states supported the war once it started.
Today there is no state in the Union that does not have at least a 1/3 minority on the “other side.”
There is absolutely no way to have a clean break or amicable divorce under such conditions. Massive ethnic and/or ideological cleansing would be required.
Which pretty much makes a mockery of this being done by “the people.” Nope, it would be one group of “the people” domineering over and oppressing another group of “the people.” Which, arguably, is what’s been going on anyway.
The only way to make this an action of “the people” is to redefine “the people” as those who support a particular political POV. Which of course makes all others “enemies of the people” even if they’re a majority in a particular area. Personally, I think the “enemies of the people” meme has a bad enough history I don’t care to revive it.
So, for the sake of ideological purity we can all rally around mittens, right?!