For me, the fundamental complaint that Putin had with the West was – West’s failure to abide by its agreement not to expand NATO east of East Germany.
Mearsheimer stated in his presentation that all his claims were documented and not just opinion. It was the basis of Putin’s 2007 Munich speech.
Putin quoted a 1990 speech by Manfred Wörner to support his position that NATO made a binding promise not to expand NATO into new countries in Eastern Europe:
He said at the time that: "the fact that we are ready not to place a NATO army outside of German territory gives the Soviet Union a firm security guarantee." Where are these guarantees?
A claim of this magnitude should certainly be documented. So I searched for a copy of the claim. All results professed “No such written agreement exists.”
I have attached two fact checks: Politifact and Brookings
Putin may have valid paranoia arguments, but this NATO claim is false.