[RobRoy]

Been to southern Cal lately? I call it northern Mexico. I have for about a decade.

[Verginius Rufus]

At least southern California is already loaded with Spanish placenames so they can keep most of them--Los Angeles, Palos Verdes, Calabasas, Santa Ana, San Marcos, Encinitas, Chula Vista, Escondido, San Bernardino, etc.

But they'll need to change "Mission Viejo" (mision is a feminine noun).