> Citing a blog post by the Brookings Institution is very funny to me

There is no shortage of sources on the ambiguity of this alleged promise [1][2]. More critically, there is a total absence of sources from Putin. Because he doesn't have any. Because when nations agree to things, they do so by issuing public declarations and/or signing treaties.

[1] https://nsarchive.gwu.edu/briefing-book/russia-programs/2017...

[2] https://www.nytimes.com/2022/01/09/us/politics/russia-ukrain...