The US can’t leave NATO, neither can any other member nation! There’s simply no mechanism for that to happen, the same applies to a member nation being expelled from NATO. At the time the treaty creating NATO was negotiated the diplomats involved never imagined a time when the Cold War would actually be over, let alone a time when a member nation would want to leave the alliance or need to be expelled from it. So they never bothered including a provision that would allow for such an event to occur. It’s just impossible for the United States to leave NATO, especially since we’re literally the founding member nation who came up with the entire concept of NATO to begin with! It would be the League of Nations all over again!
