Ukraine

Russia won't do anything to NATO regardless of what happens though. In an actual war with even just the US, Russia would crumple up, so as long as we aren't literally directly striking them, all they can do is make vague threats that they can't deliver on in hopes that western politicians who aren't knowledgable on the matter will take them seriously (which they often do unfortunately). They've been doing it all war and they keep moving the goalpoast against their own favor every time NATO calls their bluff. Honestly I've started to doubt that they even have functional nuclear warheads considering how much they say/imply they'll totally use them if NATO does X, right before NATO does X anyways... like they're compensating for not having any by pretending they have a bunch.

I think most people involved in these decisions in the US know that Russia is all bark no bite, and aren't against letting their weapons be put to use striking Russian military targets anymore. It's just putting Ukraine at a disadvantage to restrict them from using NATO weapons in Russian territory, it keeps almost all of the damage concentrated in Ukraine... obviously not very good for Ukraine.