What is never proper is for an American military officer to go to hostile foreign governments to tell them things at odds with the message the president decides to communicate. According to the book, General Milley went to the head of the Chinese military to tell him, in effect, that Trump was bluffing. He reportedly ordered naval exercises canceled to avoid offending the Chinese. He even “went so far as to pledge he would alert his counterpart in the event of a U.S. attack . . . ‘General Li, you and I have known each other for now five years. If we’re going to attack, I’m going to call you ahead of time. It’s not going to be a surprise.’”

General Milley allegedly undertook all of these steps on his own, without telling the commander in chief. It appears that he may have done so without informing the civilian leadership of the State or Defense Departments or the National Security Council. This would constitute insubordination. Douglas MacArthur and John C. Frémont were fired for less. One of the specific reasons why Harry Truman removed MacArthur was that he was pushing his own ideas to friendly and neutral foreign ambassadors without telling the president. Doing so to an American adversary would be indefensible. Promising to do so in the event of a shooting war would be an offer to commit treason.