What I think is getting scary about how immigration discourse is America is that, even when people have a disagreement that has nothing to do with race or ethnicity, it is brought into the mix anyway.
I read an article that presents an example: Immigration Debate Stirs Animosity
The causes of the incident are not clear, but two teenagers threw rocks at the vehicle of 2 Mexican men. They men had been in the park, and according to the teens, they had said something offensive to a teenaged girl (which, if it's true - thanks, guys). As they drove away, the teens threw rocks and taunted them by saying "Go back to Mexico".
A friendly neighborhood resident commented, "The whole country is getting tired of these Mexicans".
It is true that the confrontation has nothing to do with race - but it devolved into ugly chants based on the victims' nationalities anyway. And that's what I find unsettling, that it seems like more and more people are totally okay with hurling ethnic insults at people whenever a touchy situation arises, even if the initial confrontation is not racially-motivated.