I doubt it would go that far, but unless the nation's society - not just its government - gets a grip on its internecine bitterness rooted in deep racial, political and economic divisions it could wallow in ever more unrest and nastiness.
Such problems are by no means confined to the USA, but among the "developed" countries they seem particularly severe there. This may result from the country as a formal nation being still historically young, with violent origins only a dozen or so generations back and in parts, apartheid until only two or three generations ago; all implanting negative social attitudes still deeply-rooted and too easily blamed on party-politics.
This youth seems cited in a curious phrase that has arisen recently, by Americans themselves describing their nation as an "experiment". This is reinforced by many references to Amendments showing her own Constitution, a single document, can be amended as necessary. An "experiment" in what, though? To achieve what?
It is noticeable that many of SW's American users cannot discuss their own politics and internal problems objectively, constructively and analytically. Instead, they sink into partisan insults. How closely that reflects American society and politics generally, I do not know; but it is not healthy and gives we foreigners a very poor picture of the country.
It is worrying that some American analysts have raised the civil-war spectre. Talking about it as if a given, rather than how to solve the possible causes, could inadvertently make it more likely as the more nervous residents become more insular or join extremist groups, and of them the more "survivalist"-minded build up their bunkers and arsenals.
If it did happen, it could be Canada and Mexico building border walls but due to the USA's overweening (though possibly fading) world power, the political, economic and social effects would spread far beyond that continent.
