The seminal Supreme Court case that deals with the issue of birthright citizenship is United States v. Wong Kim Ark, from 1898. In Wong Kim Ark the Court held that a child of transient Chinese nationals, but born in the United States, was automatically a citizen at the time of his birth. The Court wrote, in part:
The Fourteenth Amendment affirms the ancient and fundamental rule of citizenship by birth within the territory, in the allegiance and under the protection of the country, including all children here born of resident aliens, with the exceptions or qualifications (as old as the rule itself) of children of foreign sovereigns or their ministers, or born on foreign public ships, or of enemies within and during a hostile occupation of part of our territory . . . Every citizen or subject of another country, while domiciled here, is within the allegiance and the protection, and consequently subject to the jurisdiction, of the United States . . .
And that Wong Kim “. . . if born in the country, is as much a citizen as the natural-born child of a citizen.”