Whether by coincidence or design, a good portion of Trump's supporters are white identitarian cockroaches - and Trump has done nothing to discourage such support. Spend more time perusing the dark corners of the internet and you'll see this support clearly enough. As for Trump transforming the GOP into an ethnic nationalist party, that may occur as much by moderates and conservatives bolting the GOP in disgust, leaving what's left to be on full display.
I attended the rally last Thursday in Costa Mesa. I have lived in the area for most of my life. I live among the demographics, and the attendance at the rally was a reflection of who lives here.
One surprising thing upon arriving, was how young the crowd was. Another thing easily seen, was the variety of ethnic groups in attendance.
There were far, far most Hispanics inside the rally, than the small group of violent young Marxists outside with Mexican flags.
OC demographics:
White 62.0
Black 1.7
Asian 17.8
Hispanic 33.0*
*all races
I fully expect you will claim I know nothing, etc. I was there, I saw what I saw, who was there. Learned after that one sister-in-law was there too. Of her 3 adult children, 2 are married to Hispanics. The entire extended family (Vietnam Era vet, evangelicals, etc) support Trump.
Most Hispanics in California are native born citizens. They are just as pissed about illegal immigration and crime, than anybody.
What is the Hispanic percent in YOUR area, to qualify you to opine?
https://en.wikipedia.org/wiki/Orange_County,_California#Demographics
