It is my understanding Miley can still be court-Martialed but might not have to suffer the consequences.
As the only member here that is in the middle of the road and objective, and no matter your political leaning, Miley very clearly committed Treason as did Gen McArthur and to a lesser degree Gen. Billy Mitchel.
The only reason McArthur was just relieved and not court-Martialed is it was thought a court-Martial would be a PR win for the Chinese.
As a former Army Officer I can say it was drilled into us we don't try to subvert the civilian authority over the military.
Him communicating with that Chinese Genetal , promosing to keep him aware of any plans regarding China, by President Trump, was text book treason and insubordination. It set a bad precedent for our Military.