Its what we should do....
NATO was created to keep Europe safe from expansionist countries.....Ukraine split from Russia and wants to remain free,,,,This is exactly what NATO is supposed to do,,,,It should be simple....
But, like you point out the US used its power as an empire with Iran, Iraq, Afghanistan, and others, plus south America...
The question is does the US want to get back to using its power in a moral way or as an empire....Or I Guess not at all too, unless the US itself is threatened....
Do we want to regain our moral high ground we had after WWII and fight for the little guys right to be free or do we withdraw...
Taiwan is next....