Opponents of open borders and of immigration at large draw from a variety of philosophies, moral theories, and ethical and meta-ethical traditions. Note that even if you adopt these philosophical stances, the anti-immigration conclusions don’t follow automatically but still need to be argued.

For closely related arguments about the moral permissibility of immigration restrictions, see the objections to libertarian case.

• Citizenism: The moral theory is that individuals, both in their private actions and through their elected governmental representatives, should privilege the interests and preferences of their fellow citizens over and above those of non-citizens. The term citizenism was coined by the writer Steve Sailer, but the underlying idea is quite widely accepted, even if not so clearly articulated.
• Territorialism: The moral theory is that individuals ought to weight more highly the interests of people within their nation-state and otherwise geographically close to them — including non-citizens — over the interests of people living far away.
• Local inequality aversion: This states that high levels of local inequality are per se undesirable, even if global inequality is lower as a result.
• Nation as family: This analogizes the nation to a family or a fraternal organization, where all the members look out for each others’ interests. This is a slight variation on citizenism, albeit citizenism does not by definition make use of the family analogy.