In practical terms, Donald Trump's attempt to nullify birthright citizenship by executive decree, which ran into immediate legal trouble last week, is probably the least significant element of his immigration crackdown. But it is telling as an indication of the president's willingness to disregard the law in pursuit of his agenda.
Under the 14th Amendment, "all persons born or naturalized in the United States and subject to the jurisdiction thereof" are "citizens of the United States." But under an executive order that Trump issued on his first day in office, that status would be limited to the children of citizens or legal permanent residents.
The order notes that the 14th Amendment "has never been interpreted to extend citizenship universally to everyone born within the United States." But according to an 1898 Supreme Court decision, there are just two exceptions that remain legally relevant: children of foreign diplomats and "children born of alien enemies in hostile occupation."
