Would that still convince Putin, though? Putin may be inclined to think that the messenger (CIA Director Ratcliffe) personally supports NATO, but have legit reason to doubt the support of Trump himself.
By this point, Trump has shown such a long track record of anti-NATO, pro-Putin behavior, and such a penchant for changing his mind on a topic every 3 days, that this Ratcliffe message is like pre-Holocaust Hitler sending an envoy to assure people, “I have no intention of doing bad thing to Jews.” Everyone’s response would be to raise eyebrows, “Really…?”
The presumption is that a high-ranking enough envoy couldn’t go there and say such things without the full backing of the administration. It isn’t like the director of the CIA can just go on his own initiative.
If I had to make a completely blind guess, I’d say that the grownups in the room found a way to get Trump to sign off on the visit without his really understanding what Ratcliffe was planning to do.
If so, then this means Putin still has reason to doubt Trump will defend NATO with Article 5. After all, Putin will (quite understandably) reason, “If Trump didn’t truly understand and agree with Ratcliffe’s message to me, or Ratcliffe’s purpose for visiting me, then this visit doesn’t convince me Trump will support NATO. After all, in a war, Trump will be commander-in-chief, not Ratcliffe.”
If Article 5 is triggered and Congress passes a law approving a military response, Trump would have to veto it. There’s a possible scenario after that where two thirds of the house overrides his veto, and then you’d have a constitutional crisis. That’s when the Dems will start talking about impeachment.
I could never prove it, of course … but I believe there are many probable scenarios in which Trump’s “commander-in-chief” status would be de facto kneecapped. By direct insubordination of several parties simultaneously, should it come to that – meaning that not only might Trump’s direct order to “do” or “not do” X be subverted, but also that the party responsible for physically enforcing the order (e.g. arresting the insubordinate party) will ALSO ignore their order. And then turtles all the way down. “But what if we didn’t?” can flow both ways.
Putin must understand that Trump does not have Putinian control over the Unites States of America. He has power of a kind, yes, and even plenty of it. But Trump is not now a direct analog of Vladimir Putin.
OK, but ISTM that defiance of a commander-in-chief is much easier to do when it takes the form of refusing to carry out an attack he has ordered. It would be much harder, and more unprecedented, for the defiance to take the form of fighting against Russia (as a response to Russia attack on NATO) when the president has ordered the military to stand down.