Accidental American
An accidental American is someone whom U.S. law deems to be an American citizen, but who has only a tenuous connection with that country. For example, American nationality law provides (with limited exceptions) that anyone born on U.S. territory is a U.S. citizen (jus soli), including those who leave as infants or young children, even if neither parent is a U.S. citizen (as in the case of Boris Johnson until he renounced his U.S. citizenship in 2016).