There's also historical background or subtext that seem relevant for certain interventions and that I think back to, to understand American or European thought.

• https://en.wikipedia.org/wiki/Western_betrayal (gives awareness to Polish and other central European sentiment in this conflict, that can be extremely strong)
• The instrumental arming and use of insurgencies by Americans and NATO members, see Afghanistan and the Kurds. Here is one article that seems opinionated, but gives a sense of the issues.

Another case I think back to is the Spanish civil war. 

One side, the Republications, was incredibly trendy and romanticized in the west, and enjoyed international volunteers and celebrities. A lot of world powers were involved, who provided and tested weapons that would be used later in WW2. 

In the end, the Francoist regime won, and in addition to the extreme violence during the war, for decades afterwards, Republican supporters suffered an incredibly bitter fate of impoverishment and repression.

The Ukraine conflict is very different but I think it gives caution to how outside powers, and western interest and facile romanticism can be problematic. 

It's unclear to what degree there was any underlying cause for the extreme prejudice and persecution committed by the Francoist regime. 

It seems possible this was greatly aggravated by the incredible violence of the war, which was a partially a proxy or showcase of outside powers. The suffering was immense and damage existed for decades afterwards.