Putting aside the politics of what side the US government is on...
It seems very equivalent to me to when some southern states declared secession from the northern states (in 1860), there was a civil war. To Russians, Ukraine is integral to them and their identity, even if that has been the case since 1991 (a situation forced on Russia at the time).
So, if we can leave the politics aside, accepting that there are institutions such as countries etc, what would be the right thing here?
Why should Western countries even involve themselves in this? I mean - Russia certainly is going to roll over Ukraine - how does it help anyone to arm them - isn't it just inviting more retaliation - isn't it making a bad problem even worse?