I am not here to give a dissertation on how to properly understand how the law works. If you guys want me to do so, send me a check.
Regarding John Lennon, from Wikipedia:
In 1972, the Richard Nixon Administration wanted to silence Lennon by trying to have him deported from the U.S., as Richard Nixon believed that Lennon's support for George McGovern could lose him the next election. Republican Senator Strom Thurmond suggested, in a February 1972 memo, that "deportation would be a strategic counter-measure" against Lennon. The next month the Immigration and Naturalization Service began deportation proceedings against Lennon, arguing that his 1968 misdemeanour conviction for cannabis possession in London had made him ineligible for admission to the U.S. Lennon spent the next four years in deportation hearings.While his deportation battle continued, Lennon appeared at rallies in New York City and on TV shows, including a week hosting the Mike Douglas Show in February 1972, where Jerry Rubin and Bobby Seale appeared as his guests.
On 23 March 1973, Lennon was ordered to leave the U.S. within 60 days, while Ono was granted permanent residence. In response, Lennon and Ono held a press conference at the New York American Bar Association on 1 April 1973 to announce the formation of the conceptual state of "Nutopia"; a place with "no land, no boundaries, no passports, only people", and all of its inhabitants would be ambassadors. The Lennons asked for political asylum in the U.S. while waving the white flag of Nutopia; two white handkerchiefs. The entire press conference can be seen in the (2006) Lion's Gate movie The U.S. vs. John Lennon. In June 1973, Lennon and Ono made their last political statement by attending the Watergate hearings in Washington, D.C.
Lennon's order of deportation was overturned in 1975. After Lennon’s murder, historian Jon Wiener filed a Freedom of Information request for FBI files on Lennon. The FBI admitted it had 281 pages in its files on Lennon but refused to release most of them, claiming they were national security documents. In 1983, Wiener sued the FBI with the help of the American Civil Liberties Union of Southern California. The case went to the Supreme Court before the FBI settled out of court in 1997; releasing all but ten of the contested documents. The story is told in the documentary The U.S. vs. John Lennon, by David Leaf and John Scheinfeld, released in theatres in September 2006, and on DVD in February 2007. The final ten documents in Lennon's FBI file were released in December 2006.
In 1976, Lennon's U.S. immigration status was finally resolved favourably, and he received his green card. With the departure of Nixon from the White House, his successor, Gerald Ford, showed little interest in continuing the battle. When Jimmy Carter was inaugurated as president on 19 January 1977, Lennon and Ono attended the Inaugural Ball.