Being a U.S. citizen is…
Being a U.S. citizen is very secure. So secure, that not even the President can take it away. The only way you can lose your citizenship is if you choose to give it up yourself, or if a federal court decides to cancel it because you lied or broke the law when you first got it. In O'Donnell's case, he's just mouthing off a(nother) diversion of the Epstein files.