SCOTUS Unanimously (9-0) Rules Against Illegal Aliens Seeking to Permanently Stay in U.S. Of Note from the Ruling: "Section 1255 provides a way for a “nonimmigrant” — a foreign national lawfully present in this country on a temporary basis". Meaning. A person who "legally" enters the United States is not an "immigrant" until they apply to become "Naturalized". With the approval of the U.S. Citizenship and Immigration Service (USCIS) one becomes an "immigrant". Entering the United States illegally makes the "illegal alien" ineligible for citizenship. The actual ruling: