Various media outlets are reporting that President Trump is considering an executive order modifying rules on birthright citizenship. They are also typically reporting or heavily implying that this order would violate the Constitution. I think the issue is more complicated than it’s being portrayed.
There are two separate issues, (a) whether the Constitution allows the U.S. to deny birthright citizenship to the U.S.-born children of illegal immigrants, and (b) if so, whether the President can do it on his own, without an act of Congress. I’ll leave the second question to one side, as I think it’s mainly a question of administrative law.
I assume the President’s order would amount to a reinterpretation of existing statutory citizenship law; it seems clear that the President does not have independent power to vary the citizenship laws, but arguably he has power to change the administrative interpretation of them. (As an aside, though, my guess is that if the issue ends up in court, the most likely outcome would be for the courts to find that the President lacks power to change the rules on his own and thus avoid reaching the constitutional question).
On the constitutional question, as I have written several times in the past (e.g., here, with links to earlier posts), I think the original meaning of the Fourteenth Amendment is clear in granting birthright citizenship to U.S.-born children of illegal immigrants. Briefly:
The Amendment says that “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States…” It was a bedrock principle of nineteenth-century international law that sovereigns had complete jurisdiction (that is, authority to prescribe law) over all persons and things within their sovereign territory.
This principle was subject to several exceptions, notably (1) territorial jurisdiction did not extend to ambassadors and other diplomatic personnel, nor to foreign rulers and their property, all of whom had immunity from the laws of the territorial sovereign; (2) territorial jurisdiction could be limited by treaty, as the U.S. did to some extent in treaties with Indian tribes; and (3) territorial jurisdiction did not exist as a practical matter over hostile armies and in areas under hostile occupation.
These principles are described in Chief Justice Marshall’s opinion in The Schooner Exchange (1812) and in widely read international law treatises of the time.
U.S.-born children of illegal immigrants do not fit into any of the exceptions to territorial jurisdiction. Nor is there any doubt that such children are governed by U.S. law at the moment of their birth. Thus they are “subject to the jurisdiction” of the United States at birth. As a result, the text’s original meaning grants them U.S. citizenship at birth.