The US is to blame for so so so much in this conflict, but obviously not for Russia making the choice it made. National security is a relationship, not a state of being. A nation's national security is dependent on the national security of every other nation. It's a system. Russia attempted to work with NATO, even attempting to join it, because everyone knows that national security is an interrelational framework. The US refused to admin Russia. The US refused to do anything to advance Russian national security for decades. The US explicitly stated that Russian national security is not relevant. The US explicitly acted against Russian national security interest and explicitly refused to negotiate anything that had to do with Russian national security.

The US worked for decades to get Ukraine to join NATO, up to and including supporting a violent right wing coup, sending its war heroes and its statespersons to support every anti-Russian movement in Ukraine. It worked hand-in-hand with Ukrainian military forces to establish anti-Russian capabilities and pave the way for nuclear capabilities owned and operated by the US to be deployed against Russia on Ukrainian soil.

And the US knew this would trigger an attack for 30 years. Literally as far back as Clinton the US was in talks with Russia about how Ukraine must remain neutral for Russia to be nationally secure, and documents from that time show Clinton and his administration leaving those talks and immediately talking about how to get Ukraine to join the North Atlantic bloc and turn against Russia.

Ukraine is the physical territory through which Russia was brutally invaded twice, most recently by the Third Reich. It is not appropriate to look at Russia's decision to invade and limit your analysis to that one moment. The US has spent 30 years creating this conflict, deliberately, and it has cost the Ukranians their lives and their country. And then the US did exactly the one thing that would cause more Ukranian deaths once the conflict started - it fed them arms. Ukraine's is tiny compared to Russia. It has no chance to defeat Russia. Feeding arms into the conflict means the proxy continues to fight and continues to draw more fire and continues to die at larger and larger numbers. Literally every conflict the US has pumped arms into shows this result. Had the US simply stopped it's program as soon as Russia invaded, the Russian SMO would have succeeded much more quickly with far less damage. Instead, the US has shown us exactly what it's doing - it's building it's own military capabilities to fight China while attempting to weaken the Russian position by sacrificing Ukraine for it's strategic goals.

The US had 30 years to stop this. Russia made many attempts over the years to demonstrate that the US program needed to stop because national security is non-negotiable for every single nation on the planet. But the US chose death for the Ukrainians and continued it's program knowing full well that Russia would eventually be forced to react or be subjugated. That Russia reacted when it did was a matter of Russian strategy and military intelligence. That Russia reacted at all was the known outcome of US foreign policy in Ukraine for 30 years and every diplomat, politician, and military analyst knew it.