Having lived in Arizona for much of my life, I saw what happened when migrant workers flooded into the local economy. Wage earners in landscaping, carpet-laying, roofing, painting, construction and all other trades were undercut by migrants. Schools were forced to adapt, oftentimes poorly, to the influx of students with no or little English language skills.
Hospital emergency rooms became more crowded. Law enforcement had its hands full. Legal spats from activists were constant. The unique culture of the community changes.
I realize that there are folks who disagree, but I think it is a good thing that the Border Patrol checks citizenship. If we had a national identity card, or just a Social Security number, everyone stopped could be checked. Then profiling would not be an issue.