The people of Ukraine didn't want to be Russian, they wanted to be more like the West. Their leader at the time wanted Ukraine to get in bed with Russia and the rest of the East. They ousted him. Putin seized on their moment of weakness and instability by invading.

Could the US have played a role? Yeah but every country with the ability to project any power almost certainly did as well. That's just geopolitics at work for better or worse.

Every single country on Earth exerts influence on the others to benefit themselves. Look at Ukraine cozying up with the West right now to get weapons and notice how the US, UK, and other Western nations are happily obliging. Ukraine wants to be Western and the West would love another long-term ally, especially one next to Russia. Anyone really think Eastern nations don't do the same thing? China is exerting a ton of influence in Africa right now, and it's not out of the goodness of their hearts - it's quite predatory actually so they're no different than the US in that regard.