The main victims of immigration restrictions are potential immigrants themselves. But, as Chandran Kukathas of the London School of Economics explains in a powerful recent article, immigration restrictions also undermine the freedom of natives:

The governments of most European states are eager for foreigners to enter their countries and often boast of their success in attracting people to come in as tourists… Foreigners are welcome, if they are of the right kind, come for the right reasons, and stay for the right length of time. The more the merrier. Provided everything is kept under control. But control—even attempted control—comes at a cost. One of those costs is the freedom of citizens and residents….
Regulating immigration is not just about how people arrive, but about what they do once they have entered a country. It is about controlling how long people stay, where they travel, and what they do. Most of all, it means controlling whether or not and for whom they work (paid or unpaid), what they accept in financial remuneration, and what they must do to remain in employment, for as long as that is permitted. Yet this is not possible without controlling citizens and existing residents, who must be regulated, monitored and policed to make sure that they comply with immigration laws….
Immigrants are not readily discernible from citizens, or from residents with ‘Indefinite Leave to Remain’, especially in a multi-ethnic and multi-cultural society. So any effort to identify and exclude or penalize immigrants will generally require stopping or searching or questioning anyone….
Immigration controls are controls on people, and it is difficult to control some people without also controlling others. Sometimes it is because it is not easy to distinguish those over whom control is sought from those who are considered exempt. At other times it may be because it is not possible to restrict particular persons save by coopting others without whose cooperation success would be impossible. And on occasion it may be necessary in order to control a few to put the liberty of almost everyone into abeyance. Immigration controls are not unique in this respect—the logic of human control is everywhere the same.

As Kukathas emphasizes, immigration restrictions undermine the freedom of natives for many of the same reasons that apartheid in South Africa and (and, I would add, racial segregation in the United States) violated the liberties of whites, as well as blacks. Both involve large-scale efforts to separate groups many of whose members want to interact with each other in ways forbidden by the state. Racial segregation required extensive government regulation of members of both races, even if the burden fell far more heavily on blacks. Similarly, restrictions on immigration cannot be effectively enforced without also imposing serious restrictions on the activities of natives.

Most of Kukathas’ examples come from European immigration policy. But many of the same issues arise in the United States. Just last year, for example, the Obama administration decided to perpetuate racial profiling in the enforcement of immigration law. The most liberal administration in recent memory – headed by the first African-American president – decided to continue a policy of large-scale racial discrimination because Department of Homeland Security officials insisted that there was no way to enforce US immigration restrictions without it.

This should be objectionable to left-wing critics of racial discrimination in law enforcement. But it should be equally troubling to conservative advocates of “color-blind” government. If we truly believe, as Chief Justice John Roberts puts it, that “[t]he way to stop discrimination on the basis of race is to stop discriminating on the basis of race,” we cannot allow a giant exception to this principle when it comes to immigration law enforcement.

Mandatory e-verify – a popular proposal for preventing employers from hiring illegal immigrants – is a serious danger to the freedom of natives, as well. Similarly, efforts at mass deportation of illegal immigrants – such as that proposed by Donald Trump – inevitably inflict extensive civil liberties violations on natives.

Some advocates of immigration restriction fear that unchecked immigration might itself be a threat to the freedom of current American and European citizens. I have argued that such concerns are usually overblown and, even where valid, can often be addressed by means less draconian than consigning would-be immigrants to lives of poverty and oppression in the Third World.

But, at the very least, the potential threat posed by immigrants should be weighed against the severe restrictions on natives’ liberty created by immigration restrictions. I don’t deny that there might be extreme cases where forbidding immigration by some groups is the only way to prevent even greater evils. But before we advocate immigration restrictions as a tool for protecting freedom, we should carefully consider the risk that the cure will exacerbate the disease.

UPDATE: I initially neglected to include a link to Kukathas’ article. I apologize for the omission, which has now been corrected.