It's easily explained. Putin feels betrayed by NATO. It had agreed that no new NATO member countries would border on Russia. That didn't happen. After Russia barely survived two massive military invasions from the west in the past, I'm not surprised Putin wants to gain control for part of or all of Ukraine.
The left and right can't agree on who is winning the Ukraine War. I suppose we'll find out for sure when one side runs out of soldiers and/or ammunition. The outcome will be delayed if NATO soldiers join in to help Ukraine.
He invaded Ukraine because they had allied with NATO and EU and asked for permission to join both. Because they politically no longer wanted to align with former Warsaw PACT nations. NATO won't admit a country while it is in conflict so this prevents that.
The no border countries agreement never happened and was turned down many times when requested by Russia. NATO has never saught enlargement but as accepted requests for other countries to join.
"Such an
agreement was never made. NATO’s door has been open to new members since it was founded in 1949. This has never changed. No treaty signed by NATO Allies and Russia included provisions on NATO membership. Decisions on NATO membership are taken by consensus among all Allies. Russia does not have a veto.
The idea of NATO enlargement beyond a united Germany was not on the agenda in 1989, particularly as the Warsaw Pact still existed until 1991. Mikhail Gorbachev said in an interview in 2014: "The topic of 'NATO expansion' was not discussed at all, and it wasn't brought up in those years. I say this with full responsibility. Not a single Eastern European country raised the issue, not even after the Warsaw Pact ceased to exist in 1991. Western leaders didn't bring it up either."
Individual Allies cannot make agreements on NATO’s behalf. President Clinton consistently refused Boris Yeltsin's offer to commit that no former Soviet Republics would join NATO: "I can't make commitments on behalf of NATO, and I'm not going to be in the position myself of vetoing NATO expansion with respect to any country, much less letting you or anyone else do so… NATO operates by consensus," he said.
The wording “NATO expansion” is already part of the myth. NATO did not hunt for new members or want to “expand eastward.” NATO respects every nation’s right to choose its own path. NATO membership is a decision for NATO Allies and those countries who wish to join alone."
Ukraine also agreed to give up their nuclear weapons in 1997 on the stipulation that Russia and US would never attack it.
NATO troops won't be involved unless nuclear weapons are used and it deems that action a direct threat to the member nations. Again DEFENSIVE ALLIANCE.
How many times has EVERY European country been invaded. Look at Poland or the Netherlands. Should they attached Germany to push their borders out and create a buffer. Russia in the last 100 years has invaded MANY countries in attempts to take territory.
Doesn't matter who our political left and right think is currently winning, you provide support to the side you support whether they are winning or not.
Russia won't stop until they are driven out, they don't care about people, theirs or Ukraine's and will vontinue to send in soldiers even without ammunition (already doing this by the way).