Throughout the presidential campaign, there was much talk of a Muslim registry. Fortunately, that seems to have fallen by the wayside since the election, and the Trump administration has been consistent, thus far, in denying it will pursue one. Still, we should remain vigilant about it because something similar is still on the table: a revived NSEERS program. And that program is unjust.
Active between 2002 and 2011, the National Security Entry-Exit Registration System (NSEERS) required foreign visitors from 24 Muslim countries and North Korea, regardless of religious affiliation, to register with the Department of Homeland Security (DHS) when they entered the country. These visitors were also required to check in to a DHS facility on a yearly basis thereafter and to inform DHS if they moved or had a change in employment. Citizens, green card holders, and visitors from other countries (including other Muslim-majority countries) were not included.
NSEERS could easily be revived and, given the anti-Muslim tenor of the new administration, a reinvigorated system might require temporary visitors from any Muslim country to register with DHS.
What should we say, then, about an attempt to revive NSEERS? Consider a thought experiment:
Imagine I invite you into my home. We sit, have a meal, talk, and enjoy each other’s company. You ask for the restroom, and I point you to it. You leave my eyesight to use the restroom and I relax, awaiting your return. I relax because I invited you in and trust that you will not be doing anything untoward.
Now imagine that instead of relaxing and staying in my seat, I stand and follow you to the bathroom, listening at the door. In this scenario, something unacceptable is happening.
Now imagine that you travelled far to visit and are spending the week with me. I give you the spare key so that you are not limited by my schedule, but I insist that you call me every two hours. In this case, too, something is unacceptable.
In the second short visit, it would be reasonable for you to say, “I appreciate your hospitality, but following me to the bathroom is disturbing. I will leave now.” In the longer visit, it would be reasonable for you to say, “I appreciate your hospitality, but having to call you every two hours makes it less worthwhile. I will go to a hotel.” In both of these cases, we treat our visitors like they are criminals — which is to say, we treat them disrespectfully. We might do better to not invite them at all.
The analogue here should be clear: if we are going to allow visitors in the US, we should not treat them with contempt. We should assume they are peaceful. If we have good reason to think they are not, we should not let them in at all. Accepting guests into one’s home, one’s place of business, or one’s country requires treating them with respect.

Accepting guests into one’s home, one’s place of business, or one’s country requires treating them with respect.”]
If US citizens want to have foreigners in the country, those foreigners must be treated with respect — and requiring that they check in with DHS on regular intervals is not treating them with respect. There are things a legitimate government cannot do. It cannot imprison innocent people or those that it deems subversive because they disagree with its policies. It cannot bomb areas of the country where residents disapprove of its actions. In short, it must show proper respect for its citizens. And showing proper respect for its citizens requires showing proper respect for their visitors.  Plausibly, we do this with the US-VISIT program (now the Office of Biometric Identity Management Identification Services), which is also more efficient while inviting less descrimination. There is, thus, no reason to even consider the disrespectful behavior of a revived NSEERS.
Of course, it is possible that limiting visits to the US to those from non-Muslim countries is needed to protect Americans. If that were the case, I suspect the majority of US citizens would be in favor of limiting those visits — not just continuing visits by some that are then disrespectfully monitored. But that is a different issue altogether — and one for which we have no evidence. Once we have determined that a visitor may safely cross the border into our country, we should treat them like we would treat a houseguest. With respect.