Well, Ukraine wanted to join NATO, so the US could have given them a security guarantee for if Russia invaded further than Crimea. Russia never wants to be seen

Well, Ukraine wanted to join NATO, so the US could have given them a security guarantee for if Russia invaded further than Crimea. Russia never wants to be seen as the ones causing escalation, even when they are, so it seems unlikely they'd have tested that guarantee. Would have saved a lot of lives. Looking at what happened, it would also have saved a lot of lives if the US and allies had used their air forces to remove Russia at the beginning of the conflict. Never agreed with the assessment that would lead to ww3 or nuclear exchange, Russia would lose or everyone would lose in both cases.