We have NO national interest in Ukraine.
1. Our commitment to Ukraine inducing them to eliminate their nuclear weapon arsenal inherited from the Soviet Union that we would safeguard them.
2. Preserving ability to enlist allies in any cause, for example, against Chinese aggression in the Western Pacific because we are known to abide by our commitments.
3. To compensate for our loss of face stemming from our humiliation in Afghanistan.
4. To maintain the principle of the inviolability of national borders.
5. To prevent the Black Sea from becoming a Russian Lake threatening Bulgaria, Romania, Turkey etc.
7. To prevent Russia from succeeding in a dividing and conquering strategy in Europe, separating America from NATO, arousing popular discontent among populations leading to virtual surrender to a China/Russia behemoth.
To repeat: these are interests recounted on-the-fly which must be considered, I do not say that they necessarily mean that we should go to war. Do they mean that we might consider further arming Ukraine?