NATO has the deterrence. The deterrence has come from article 5 applied to NATO territory. There was no NATO or Canadian deterrent put in to defend Ukraine. In fact, before the war started, President Biden said very clearly that NATO would not go to war and the United States would not go to war against Russia over Ukraine. Ukraine never had a deterrent. It always had to defend itself, with western support.
Deterrence is really linked to nuclear weapons. You have conventional defence and nuclear deterrence. NATO functions like that. It has the two.
All NATO territory has the benefit—like the Baltic states, so Poland and that area—that should Russia attack, the initial defence would be the conventional forces. However, NATO has the right at any point in time to use nuclear weapons to defend itself should the conventional defence fail. That's where the nuclear deterrent comes in.