If you’re on board with the libertarian case for open borders, and believe that the right to migrate applies at least presumptively, the next task on hand is to identify the exceptional situations where this right may be curtailed in the form of a blanket denial. I’m distinguishing blanket denials from immigration tariffs and other keyhole solutions that require potential immigrants to spend a “reasonable” amount of time, money, or effort in compliance.
My thumb rule for blanket denials is: anything that constitutes sufficient reason for blanket denial of migration should also constitute sufficient reason for punitive measures under criminal or civil law in the target country of immigration. For instance, murder is sufficient grounds for imprisonment, and hence also, in my book, sufficient grounds for a blanket denial of the right to migrate. In some cases, I think the punitive measure under domestic criminal law really is morally unjustified, and hence restricting immigration on that basis is also unjustified. An example is laws against drug use in many countries — I don’t think drug use is sufficient grounds for imprisonment, and hence also not sufficient grounds for denying immigrants entry. But others, who hold different views on drug use, may come to the opposite conclusion.
So far, so good. It is when we move from criminal law to civil law that things get more interesting. Certain activities, such as libel, contract fraud, and copyright infringement, are punishable under civil, but not criminal, law in most jurisdiction — they are litigated by persons, not prosecuted by the state. Libertarians (and others) are probably unanimous about the evil of contract fraud, and may have the view that, at least in some extreme cases, this may be sufficient grounds for denying the right to migrate. Libel and copyright infringement are trickier, since many libertarians (and others) feel that copyright infringement is not immoral at all, and some hold a similar view about libel. Even for those who are opposed to libel and copyright infringement, deporting people, or denying entry, for these “crimes” may seem like overkill. Other minor “crimes” like traffic infractions may also seem like insufficient grounds for denying the right to migrate.
The most interesting case, though, is the case of people holding and espousing viewpoints that are perfectly legal — in compliance with criminal law and unlikely to be successfully litigated against. First Amendment protections in the United States give people wide latitude to say a lot of things as long as these do not constitute libel/slander, infringe on copyrights, trademarks, or patents, or provide direct incitement to violence in a situation where such violence may be carried out. There are various restrictions in the United States on pornography and speech directly related to political candidates, but I’m ignoring these for the moment. In particular, it is perfectly okay from a legal viewpoint to say positive or negative things about century-old religious doctrines, regardless of the truth or falsehood of these. You could praise Christianity or Islam or Buddhism or Hinduism, or condemn these, and no legal action against you would plausibly succeed. It is also perfectly okay from a legal viewpoint to hold and espouse practically any political position from communism to Nazism to anarcho-capitalism.
Going by my thumb rule, then, viewpoint-based immigration restrictions are not morally justified. However, a number of people, even those broadly supportive of open borders, do express some sympathy for the concerns that underlie the advocacy of viewpoint-based immigration restrictions. The whole political externalities argument — which focuses on how immigrants’ political beliefs would affect political policies and outcomes — is an example. Another example is offered by my co-blogger Nathan Smith, who, in his book Principles of a Free Society, carves out a possible viewpoint-based exception to his general advocacy of open borders — the case of Islam. Given his devotion to open borders, he endorses an intermediate solution, but it still falls short of the thumb rule I outline above.
Unless it were deliberately modified to avert this result, DRITI [Nathan’s shorthand for his proposed immigration plan — “Don’t Restrict Immigration, Tax It”] would lead to large-scale immigration of Muslims in search of freedom and economic opportunity, and this is one of the more legitimate reasons to worry about it. Worldwide, Islam exhibits a large democracy deficit vis-a-vis the rest of the world (Rowley and Smith, 2009), partly because of the historical lack of a tradition of freedom, and especially of religious freedom, in Islamic societies. On the other hand, there are now quite a few Muslim-majority democratic countries, such as Indonesia. […] Mass Islamic immigration could lead to Muslim majorities in host countries, able to replace freedom with Islamic sharia.
The most drastic response to this threat would be simply to exclude Muslims from eligibility for DRITI visas, or perhaps from the path to citizenship associated with it. It is tenable that the mere fact of adherence to Islam is evidence of a commitment to values inconsistent with respecting the rights of others that justifies excluding a person as a security threat. [emphasis added, not in original] This would be unfair, however, to those Muslims, probably constituting a large majority, who have no inclination to accept and/or to act on this (arguable) tenet of their faith. […] A more moderate approach might be to screen carefully for known terror suspects and extremists, to keep a close watch on Muslim immigrant communities, and to inquire into the ideology of Muslim DRITI migrants applying for citizenship to make sure they convincingly disavow the death penalty for apostasy and other traditional Islamic beliefs inconsistent with the principles of a free society, perhaps with the help of oaths or signed statements to that effect.
The reason I think this falls short of the thumb rule I advocate is that I doubt that Nathan would agree to the idea that if a person who is already a US citizen advocated, say, the death penalty for apostasy from Islam, then that person should be prosecuted or successfully litigated against. Or even that this person should be stripped of his/her citizenship.
Personally, I do not have a firm opinion on whether viewpoint-based immigration restrictions of this kind are morally justifiable. One possibility is that my thumb rule is, in fact, wrong, and such restrictions are morally justifiable, even though citizens who espouse similar viewpoints are legally protected. Another possibility is that the restrictions are not justifiable. A third viewpoint is that, in fact, the restrictions are justifiable and that citizens who espouse similar viewpoints should not enjoy legal protection.
What we should keep in mind, though, is that even if such viewpoint-based immigration restrictions are morally justified, there is still a pretty substantial extent to which immigration can be made freer while maintaining such restrictions.