The Trump administration is arguing that birthright citizenship is not guaranteed by the Fourteenth Amendment. Since the Amendment's adoption in the 1860s, advocates of immigration and widespread naturalization have argued that the amendment applies to anyone born on US soil, even if his or her parents are only temporarily traveling within the US. Others have argued that the amendment was intended as a measure designed only to avoid statelessness for former slaves and their children in the United States. That is, the amendment was a post-Civil War measure designed to address a problem of the time. 

I have covered this controversy in some detail in an article titled "Birthright Citizenship Isn't Real." That article, however, was centered on legal arguments. Whatever one makes of claims surrounding the constitutionality of birthright citizenship, legal arguments alone can't establish a moral case for birthright citizenship, or establish citizenship as a natural right. A government-created legal "right" is not the same thing as a natural right. History has shown that government judges and their allies argue for all sorts of special legal "rights" that are not derived from natural rights at all. The Supreme Court has ruled, for example, that residents of the US effectively have a "right" to public schooling—paid for by taxpayers, of course—under the so-called equal protection clause. Government judges have also decided that US residents have a "right" to kill human babies in utero, and a "right" to vote. None of these "rights," however, are based on any property rights derived from the natural rights of life, liberty, and property. The legitimate natural rights—as explained by early classical liberals such as Thomas Jefferson and John Locke—are founded in legitimately held property, such as that acquired through homesteading, peaceful exchange, or the natural ownership of one's own physical body. 

Birthright citizenship, on the other hand—i.e., automatic naturalization based on the political jurisdiction in which one is born—is one of these invented legal "rights." 

This helps explain why, among those who claim to be the protectors of property rights—i.e., many self-described "libertarians"—we virtually never encounter an argument for naturalization based on property rights. For example, in a new press release from the CATO institute, emailed out this morning in response to oral arguments at the Supreme Court (see below), all of the CATO scholars quoted rely entirely on legal arguments about constitutional law and on consequentialist claims about alleged benefits of federally-mandated mass naturalization. Private property is never mentioned. David J. Bier does mention "rights of every...citizen" but, tellingly, no actual property rights are mentioned.1

Yet, even if we are talking about protecting the property rights of non-citizens, that is an entirely separate question that does not depend on naturalization or citizenship.  If the question is "do non-citizens have property rights in the United States?" the answer is an emphatic "yes." The Bill of Rights, after all, clearly doesn't limit itself to citizens. Moreover, the Bill of Rights does not guarantee a right to naturalization or, by extension, a right to vote. In other words, the authors of the Bill of Rights clearly did not view "rights" as reliant on the government-issued status we call "citizenship." This is because classical liberals in the eighteenth and nineteenth centuries did not believe that voting and citizenship were akin to property rights like "life, liberty, and property." (I explain in more details in this article.)