What about Mr Trumps "Board of Peace"? Would this creation of his not be a logical place he could turn to in case of need?
After all, NATO is a defensive alliance. As none of its member states are under attack at the moment, it is not immediately obvious to me why it should ride to the rescue.
Also, the official way of setting NATO in motion is not a post on whatever that message board of Mr Trumps choice may be called at the moment, it requires formally invoking
Article 5 of the North Atlantic Treaty, to which the US as a partner in this treaty would have a right, were they so inclined. They did once already and had their friends and partners come to their aid, as we all remember.
What NATO is clearly not is a "Get out of Jail" card. It is a defensive alliance, never having been intended to ride to the rescue when someone, purely hypothetically, may have started a war that was later found out to have been ill advised, badly planned, and not going into the desired direction.