https://www.uscis.gov/tools/designated-civil-surgeons/vaccin...
https://www.uscis.gov/tools/designated-civil-surgeons/vaccin...
Immigration to the U.S. is of course, a regulated activity. They can make you take a physical, pay a fee, inspect your background, call your mom and make sure you're a good person, etc, before accepting you as an immigrant. Sure. There's no limits to that, because there's no U.S. Constitutional protection for non-U.S. citizens and immigration can be stopped altogether if desired (assuming it's enforced).
The fourteenth amendment plainly says “people” not citizens. There are others, but this is the most obvious one.
> nor shall any State deprive any person of life, liberty, or property, without due process of law;
But this kind of arguments are precisely the point when it comes to concern about precedents. It becomes less of a barrier to adding new rules just because the law already has vaguely similar rules.
https://ec.europa.eu/home-affairs/what-we-do/networks/europe...
All rights have limitations of course.