It isn't credible now. It likely won't exist at all in 4 years. Unless it cedes even more decision making authority to the US and becomes even more of a puppet.
I doubt there's anything that will sway them. My guess is he's in massive financial debt to the Russian mafia or directly to Putin. He's afraid of being suicided out a window defenestration style.
Doesn't all authority already lie with the USA? If we're going to be real, I mean. I'm sure France thinks otherwise but let's be real: NATO was always the "Uncle Sam will protect Europe from Russia"-treaty.