The 1917 Immigration Act shows how aliens are those who are not native-born or naturalized citizens of the United States. As the term native-born is well understood, this shows once again how Congress considers the status of children born abroad to citizen parents to be naturalized.
Act of February 5, 1917
Immigration Act of 1917, Regulating the Immigration of Aliens to and Residence of Aliens in the United States
39 Stat. 874
Sec. 1. That the word “alien” wherever used in this Act shall include any person not a native-born or naturalized citizen of the United States; but this definition shall not be held to include Indians of the United States not taxes or citizens of the islands under the jurisdiction of the United States. That the term “United States” as used in the title as well as in the various sections of this Act shall be construed to mean the United States, and any waters, territory or other place subject to the jurisdiction thereof, except the Isthmian Canal Zone…