This is Gorbachev's statement on the matter:
There have been some other quotes posted here and other materials where some talk exists that maybe some sort of verbal "promise" may have been offered to Gorbachev, but I think it's as Willie says. Even if Baker and Bush at the time said no NATO expansion east (I'm simplifying the language here) it would not be a valid promise to make, for many reasons. No ratification would be one. Not written down. But even if written down, Bush/Baker could not make promises for future US administrations, nor was any treaty ironed out as to how long this would last and what it would entail. Finally USSR was no more. Gorbachev would have to be a naive amateur to take any such jest at face value or any serious Russian politician to really believe this would mean anything.
Western leaders gave multiple assurances against NATO expansion to Gorbachev in 1990-1991 according to declassified American, Russian, British, Germans documents
nsarchive.gwu.edu
Of note, Mitterrand of France at the time said this:
"The French leader Francois Mitterrand was not in a mind-meld with the Americans, quite the contrary, as evidenced by his telling Gorbachev in Moscow on May 25, 1990, that he was “personally in favor of gradually dismantling the military blocs”
Was this a promise too? Because that hints at a promise, an implied *wink* *wink* type of promise. So why are Russians not upset with Macron for not following up on what Mitterrand hinted at?
Despite all of this, this is all BS, because Gorbachev knew that without ratification and ironing out what NATO expansion meant and how long and where etc... any sort of nudge nudge warm fuzzies agreements would mean nothing or at best would not take advantage of the USSR at that very point. And to be fair NATO did not enlarge for a long time. American forces were not hosted in former Eastern Europe for years after that.
So it's all moot. If Gorbachev was taken in by a warm feeling in his bosom, well that sucks on him. Strange that a career guy who worked his way up to Comrade 1st Secretary would be this gullible, naive and stupid. I would say he wasn't. He knew these "promises" were worthless or he'd insist on proper treaties, changing the status of NATO constitution to explicity exclude Hungary, Czechoslovakia etc from NATO in all perpetuity etc...
And to hold the US to nebulous, non detailed and not ratified agreements is stupid of Russia and their peanut gallery of shills.