John Mearheimer explains why the West did not try to prevent Russia invading Ukraine by offering concessions

 "And then the war starts and the Russians immediately reach out to the Ukrainians to talk about negotiations to end the war. This is right after it starts. The Russians want to end it. The Ukrainians agree and the famous negotiations in Istanbul start. And as you well know, who ends those negotiations? It's not the Ukrainians. It's not the Russians. It's the Americans and the British in the form of Boris Johnson who come in and tell the Ukrainians that they should walk away from the negotiations. Now, you want to ask yourself, what's going on here? What's going on is we thought that we could defeat the Russians. This is why we didn't try to prevent the war and why once it started, we didn't go along with Putin's efforts to stop the war. We thought we had the Russians and Putin right where we wanted them. We thought that we had armed and trained the Ukrainians to the point where they could hold their own on the battlefield. And furthermore, economic sanctions would deliver a really staggering blow to the Russians. And that combination of economic sanctions plus defeat on the battlefield would knock the Russians out of the ranks of the great powers and it would end up with Putin falling from power.

"....Of course, we were categorically wrong. One could say catastrophically wrong. And the people who are paying the price for our foolishness are the Ukrainians."

The interview from which I quote is here.

Although I blamed the Americans and British for not offering Russia reasons to to forego an invasion I only now suddenly see defeat for Russia and regime change in Moscow was the objective of people like Victoria Nuland, Joe Biden and the rest of the crew, probably from before the war started.

This is the same American bipartisan defence establishment that rightly protested about Putin's murderous war but finances the IDF.