> Russia was promised no NATO expansion when the Warsaw Pact was terminated.

That is factually incorrect. There is no treaty, no memorandum, no statement about that, except for some hearsay from a meeting between Baker and Gorbachev. This is the treaty about east Germany https://usa.usembassy.de/etexts/2plusfour8994e.htm and NATO, which the west has respected. Stop spreading misinformation.

What is correct is that Russia promised guarantees of Ukraine's borders in the Budapest memorandum.