The U.S. has a long history of demographic targetting. It's not a history most are proud of and boast about. i.e., slavery, blacks openly treated as second class citizens, tolerance of the KKK to "manage" the problem, McCarthyism and communism,Cuban immigrants, Vietnamese boat people during the 70's, most recently the fear mongering created over Muslims........and this law fits right there amongst that way of thinking. Is it any wonder the U.S. struggles to put a positive light on their foreign policies?
This law won't reduce the number of illegals. There are just way too many. It won't stop cross border smuggling and illegal border crossings. It will simply cause illegals to locate out of Arizona once they have crossed the border. It's more or less a passing the buck kind of law.
Laws were already in place that enabled law enforcement to detain illegals if they were caught during routine identity checks. This law now creates this huge grey area of "reasonable suspiscion". It opens the door to racial profiling. It will happen. By nature, police will use and manipulate whatever tools they have at hand. This law provides just that "loophole".
Then again, I wouldn't expect anything less from the land of McCain.