Some of the population, especially in the more democrat areas in inner-city Phoenix-Metro (basically Gijalva's district down to UofA) are really buying into it. Helped by Academia, and what passes for "latino" media. You can see them "rise up" as it were during the demonstrations against Arizona's immigration law where they threw water bottles at police. I think it was at that point that they realized that only about 1000 people, most high school/college students that showed up out of well over 4,000,000 people in the city. I think most of their parents must have been irate over the protests because they smaller and smaller after that.
There are two things Phoenix isn't short on. 1.) Upstanding citizen guns owners. 2.) Sheriffs who will deputize civilians. That pretty much solves the problem if it becomes one.
I'm just not sure I see this becoming a problem except in specific areas of some cities. I went to high school, the Marines, and now work with 1st generation Americans, naturalized citizens, and in high school, even knew some Mexican Nationals. They didn't seem like they felt oppressed to me, they just seemed damned glad to be here doing whatever it was they were doing.