Exactly. This is the big fear, an unannounced attack that is untraceable. It can be done if the country develops a nuclear warhead. The missile part isn’t that hard, as it doesn’t have to be intercontinental.
It is a real threat.
Yes the govt has put out a couple of articles warning about it in the last several years. I read one this past year. If you google it you can real all about it. Its a very real threat.