There’s a lot of furore over President Trump’s temporary entry ban for people of certain (Islam-affiliated) nationalities. The controversial portion of it is that citizens of seven identified countries – whether or not they also hold citizenship from another nation – are not allowed entry visas to the United States for 90 days to ease the burden on the Department of Homeland Security while it revamps its screening programs. (The order also expedites a number of screening programs that were to be put in place anyway and orders a thorough review of existing programs to ensure they are effective over the next 120 days.) As is typical of these things, there’s a lot of overreaction and misunderstanding. I don’t claim to understand the legal nuances of immigration policy, but here’s a first stab at a position on it based on the text of the order and the Immigration Act of 1965. Broadly speaking, I think there are two potential problems with the order: (1) President Trump may have exceeded his constitutional authority in issuing it and (2) there may be independent constitutional issues with it as regards people holding already-approved-and-issued residency permits.
In general, I don’t have a moral problem with entry bans targeted to nationality, though I think it’s a complicated issue. I think there is probably a prima facie moral problem with them insofar as individuals cannot help where they are born and should not, generally speaking, be held responsible for the cultures or legal systems of their home countries. But that’s only prima facie. Nations have the right to control their borders, pursuant to protecting the interests of their own citizens, and those interests can, in individual cases, override the prima facie presumption that an individual should be able to travel where he likes. Distill that all down, and what I’m saying is that I think such bans are OK provided they’re considered and not arbitrary.
Whatever the moral issues, there is no constitutional problem with nationality-targeted immigration bans that I’m aware of. Such bans were the norm for much of our history, and I’m not aware of anywhere the courts have struck them down.
Whatever the constitutional issues, it is nevertheless specifically illegal to deny entry on the basis of nationality since the Immigration Act of 1965. That was, in fact, the main motivation for pasisng it: to overturn prior nationality-based policy. The relevant section is Section II, clause (a):
No person shall receive any preference or priority or be discrminated against in the issuance of an immigrant visa because of his race, sex, nationality, place of birth, or place of residence…
It goes on to refer to (mostly pre-existing, though some have been added since) exceptions, but as regards nationality, they all seem to refer to individual agreements with particular countries (the UK, for instance).
Since Congress has made it specifically illegal to deny visas on the basis of nationality alone, it’s my opinion that President Trump doesn’t have the authority to issue this ban. Only Congress – by repealing or amending the Immigration Act of 1965 – can issue blanket bans on immigration based on nationality. However, the temporary nature of the ban may be a mitigating factor.
Additionally, there seems to be a Due Process issue for holders of approved residency permits. To what extent foreign nationals have US constitutional rights is a thorny issue, and there isn’t any definitive answer to the question. What has been decided on this comes in the form of a patchwork of unconnected court decisions over a very long period of time. The broad answer seems to be "foreigners have some, but certainly not all, US constitutional rights, and the ones they do have they may not have to the same degree US citizens do." One category of right they do seem to have is Due Process rights. The main precedent is Kwong Hai Chew v. Colding (1952) as applies to holders of residency permits, and it’s been separately ruled (in Zadvydas et al v. Davis (2001)) that all "persons" physically present in the United States have Due Process rights, even if they’re non-citizen criminals. None of that, of course, means that people currently living in one of the seven identified countries (say, Iran) have US Due Process rights: they pretty clearly do not. But court precedent is clear that people who have already been issued a residency permit – such as a Green Card – cannot be arbitrarily deprived of it without a hearing. So, it’s my opinion that the ban is additionally unconstitutional on this ground insofar as it applies to people who were duly approved for entry before the ban went into effect.
In summary, while I don’t see any moral or constitutional issues with nationality-based bans on entry – at least as long as such bans are not completely based on whims – I don’t think President Trump specifically has the authority to issue the current ban, and I don’t think anyone has the authority to revoke already-issued residency permits en masse based on the nationality of their holders alone. Or, rather, if they do (specifically, if Congress does), the holders of these permits retain the right to challenge the decision in court.
The District Court for Eastern New York has put a stay on the order on some of these grounds already. The text of Judge Donnelly’s ruling is not yet public in full, but the link goes to a preliminary transcription of it published by Fortune.com. It doesn’t address the issue of whether President Trump exercised authority reserved to Congress in issuing the order, but it does affirm that there are Due Process issues that need to be resolved for current holders of already-approved residency permits before the order can be allowed to go into force.