No, you can't just place NATO missiles on the border just like the US freaked out about the Cuban missile crisis, which ironically was the USSR just retaliating because we placed missiles close to them in the first place.

Also another reason for the war is that we directed Ukraine to kill their ethnic Russians in the 2 independent republics. Putin complained to the UN but nobody would listen. Also we couped their government in 2014. https://youtu.be/L2XNN0Yt6D8