The Chairman of the Joint Chiefs telling the leader of the armies of an unfriendly nation that he will keep them informed of any hostile military plans IS treason. Plain and simple. If a lower ranking officer was caught making this offer he would already be facing possible execution.

If the "esteemed" General and the even more "esteemed" third person in line to assume the Presidency truly believed President Trump was so unhinged he could start a nuclear war to retain power, there's a mechanism for dealing with that. And it's not secretly sharing information with an enemy. That's the cowardly, weasel way. But it would have taken true moral courage to go public with that belief and we know that doesn't exist anymore in politics.