The US and the UK signed the Budapest Memorandum
Now THAT is an argument of substance...and a very good point. An important point about that agreement, though, was the agreement was between the US, UK, and Russia as an assurance Ukraine territory would remain intact if Uke went non-nuke. The agreement wasn't actually with Ukraine. Even certain members if the Clinton admin and the Ukrainian asmin knew it was basically worthless.
Nevertheless, it does beg scrutiny.
You might like a book called "Not One Inch" that talks about post cold war and NATO expansion. IMO, the hubris of the the US ( and other western countries) share a ton of blame for getting to where we are now. For the record, because people love to go off the rails and make cock-eyed conclusions, Putin is the only one responsible for this invasion-but he is responding to certain geopolitical realities, which, however, does not excuse his unjust invasion.