In my forthcoming graphic novel, I argue that all leading moral theories strongly support open borders.  Only yesterday, though, did I learn that philosopher Joseph Carens covered the utilitarian, Rawlsian, and Nozickian cases in a single 1987 article.  The piece: “Aliens and Citizens: The Case for Open Borders” (Review of Politics).  EconLog readers may particularly enjoy the Nozickian section:

One popular position on immigration goes something like this: “It’s our country. We can let in or keep out whomever we want.” This could be interpreted as a claim that the right to exclude aliens is based on property rights, perhaps collective or national property rights. Would this sort of claim receive support from theories in which property rights play a central role? I think not, because those theories emphasize individual property rights and the concept of collective or national property rights would undermine the individual rights that these theories wish to protect.

Carens continues:

Would this minimal state be justified in restricting immigration? Nozick never answers this question directly, but his argument at a number of points suggests not. According to Nozick the state has no right to do anything other than enforce the rights which individuals already enjoy in the state of nature. Citizenship gives rise to no distinctive claim…

Note what this implies for immigration. Suppose a farmer from the United States wanted to hire workers from Mexico. The government would have no right to prohibit him from doing this. To prevent the Mexicans from coming would violate the rights of both the American farmer and the Mexican workers to engage in voluntary transactions. Of course, American workers might be disadvantaged by this competition with foreign workers. But Nozick explicitly denies that anyone has a right to be protected against competitive disadvantage. (To count that sort of thing as a harm would undermine the foundations of individual property rights.) Even if the Mexicans did not have job offers from an American, a Nozickean government would have no grounds for preventing them from entering the country. So long as they were peaceful and did not steal, trespass on private property, or otherwise violate the rights of other individuals, their entry and their actions would be none of the state’s business.

The “right to exclude” is a right held by individual property-owners, not governments:

Does this mean that Nozick’s theory provides no basis for the exclusion of aliens? Not exactly. It means rather that it provides no basis for the state to exclude aliens and no basis for individuals to exclude aliens that could not be used to exclude citizens as well.  Poor aliens could not afford to live in affluent suburbs (except in the servants’ quarters), but that would be true of poor citizens too.
Individual property owners could refuse to hire aliens, to rent them houses, to sell them food, and so on, but in a Nozickean world they could do the same things to their fellow citizens. In other words, individuals may do what they like with their own personal property. They may normally exclude whomever they want from land they own. But they have this right to exclude as individuals, not as members of a collective. They cannot prevent other individuals from acting differently (hiring aliens, renting them houses, etc.)

What about the “utopia” part of Anarchy, State, and Utopia?

Is there any room for collective action to restrict entry in Nozick’s theory? In the final section of his book, Nozick draws a distinction between nations (or states) and small face-to-face communities. People may voluntarily construct small communities on principles quite different from the ones that govern the state so long as individuals are free to leave these communities. For example, people may choose to pool their property and to make collective decisions on the basis of majority rule. Nozick argues that this sort of community has a right to restrict membership to those whom it wishes to admit and to control entry to its land. But such a community may also redistribute its jointly held property as it chooses. This is not an option that Nozick (or any other property rights theorist) intends to grant to the state.

Summing up:

This shows why the claim “It’s our country. We can admit or exclude whomever we want” is ultimately incompatible with a property rights theory like Nozick’s. Property cannot serve as a protection for individuals against the collective if property is collectively owned. If the notion of collective ownership is used to justify keeping aliens out, it opens the possibility of using the same notion to justify redistributing income or whatever else the majority decides. Nozick explicitly says that the land of a nation is not the collective property of its citizens. It follows that the control that the state can legitimately exercise over that land is limited to the enforcement of the rights of individual owners. Prohibiting people from entering a territory because they did not happen to be born there or otherwise gain the credentials of citizenship is no part of any state’s legitimate mandate. The state has no right to restrict immigration.

I would add that if a whole country was collective property, there would be a mighty case for strictly regulating it as a dangerous monopolist.