just as the waves of goths and huns and other barbarian tribes deromanized the provinces in the Late Western Roman Empire - destroying the economy, displacing populations, changing the language and other cultural paradigms, often devaluing the land itself through damage to resources and irrigation, interrupting trade and communications, forcing the development of walled and fortified hilltop towns, and paving the way for ethnic-based feudalism...
so too does our current exactly similar policy of "defense in depth" work to destroy the southwest of this republic.
It isn't just the southwest. They're in every state of the union and don't plan to leave anytime soon.