FQ is on the right track, but it will be more complicated than that.
More like post WWI Germany.
Free Americans who can will head for the rural areas where the majority are like minded while the sheep will flock to the urban area's for govt security and maintenance. but few if any cities will be "secure" as there will be gangs, militias, deathsquads, and "peacekeepers" from all factions fighting interchangeably in the streets and alley's.