This is a great article from the Atlantic that has a fantastic response to this question about illegal immigration.
"Balderas's real crime is neither sneaking across the border 15 years ago nor failing to fill out the right paperwork. Rather, his crime is belonging to a nationality that American policy makers have decided is over-represented in this country. And there's a significant constituency for this policy among American voters, some of whom simply believe that there are too many foreigners here. But this viewpoint has little to do with the rule of law. The rule of law doesn't demand that we punish children for the crimes of their parents, or that we punish people for crimes they committed decades ago. And if you demand stricter enforcement of the existing laws while vociferously opposing all proposals to expand the legal channels for coming to this country, then I hope you'll forgive me if I conclude that you don't actually care about people like Eric Balderas." Megan McCardle