As I have repeatedly emphasized over the years, a system of immigration controls inevitably involves immigration enforcement measures. That is, when we talk about immigration controls, we are not simply referring to a sign at the border that says: “Do not enter without the official permission of the U.S. government.” No immigrant would pay any attention to such a sign. Thus, to enforce the immigration-control system, the federal government increasingly enacts immigration-enforcement measures, which inevitably involve a violation of the libertarian non-aggression principle. They stop people...
