Well, to be honest, your country attacking your country isn’t that far off with the talk about taking Greenland by force. It would kind of mean that USA is at war with itself having attacked a fellow NATO member (Denmark). Attack against one is an attack against everyone, including the USA.
–Edit–
The USA would also be required to defend Denmark against itself, which would be an interesting situation.
Well, to be honest, your country attacking your country isn’t that far off with the talk about taking Greenland by force. It would kind of mean that USA is at war with itself having attacked a fellow NATO member (Denmark). Attack against one is an attack against everyone, including the USA.
–Edit–
The USA would also be required to defend Denmark against itself, which would be an interesting situation.