This article from the Houston Chronicle highlights exactly the reason I don't have a problem with illegal immigration: it's entirely voluntary. People voluntarily come, people voluntarily rent out properties to immigrants, and people voluntary hire immigrants. People obviously also voluntarily sell food, clothing, and myriad other products to immigrants. The only thing involuntary that immigrants engage in is using the benefits of the welfare state (public schools and occasionally emergency rooms, mostly), but anyone who argues against [illegal] immigration on the basis of the welfare benefits they could receive ought to direct their ire at the welfare state itself, not the immigrants who are taking advantage of it. As Milton Friedman once said, "you can't have free immigration and a welfare state."