Comment by mopsi

There's a problem with this narrative. Everyone links the "What Gorbachev Heard" article from the NSU, but there was no reason to speculate, because Gorbachev and his team were still alive when the article was written in 2017.

Some others did reach out and ask them directly. Gorbachev, his minister of foreign affairs, and his minister of defense all publicly refuted it. It would have been a major commitment, yet there is no trace of it having been discussed internally in Moscow or with other Warsaw Pact countries. Furthermore, according to the USSR's foreign minister at the time, the speculation of such assurance is anachronistic, because the Soviet leadership did not expect the Warsaw Pact to dissolve and therefore had no reason to discuss anything like this.