@tzimmer_history You're describing is oldest trick in the book. In fact, it predates books. The trick is simply to unite the people by stoking fear of a perceived common enemy. In this case, racial (and/or religious) minorities. This fear overrides all other priorities, like the rule of law, and even voters' own self-interest.
The problem with this strategy is that it's not sustainable. The "enemy" isn't really an enemy at all. Fear subsides with exposure. Pluralism wins... eventually.