The bad news is that NATO would most likely disband over war with Russia. The good news is that the US and the UK would honor the commitment they made. FWIW, I believe France would as well.
Remember Ralph Peters old fiction work “Red Army”? I read it recently, the Russians win because W. Germany won’t sign off on the possible use of tactical nuclear weapons in the conflict and there is a cease fire right when the American forces are in the process of kicking off an offensive.
Kinda like what your saying...