I do slightly wonder if this is a bit of propaganda from the NATO side - smaller, less threatening NATO member offers significant, more provocative military aid to Ukraine if US backs them. US, who Putin is continuously expressing have supposedly been aggressive towards Russia, immediately throw their hands up and say "whoa, whoa, whoa, seems a bit escalatory, everyone calm down, probably shouldn't do that" and make a big show of how NATO aren't looking for a fight/to be involved militarily. I know he'll continue with it, but it does make it quite hard for Putin to keep up the narrative that Russia is under threat from NATO if they're demonstrably distancing themselves from the proposed actions of some member states to avoid being seen as overly aggressive.
I don't know, it's just my late night musings and I expect there's a million reasons why that wouldn't be the case, but it just seems odd that there have been rumblings of this for a week now and all of a sudden the US are acting like it's a surprise.