US never attacked China for supplying Vietnam and in
Vietnam US had 3000+ planes shot down. In fact during the height of the Vietnam war in 1972 Nixon went hat in hand to Beijing.
It's funny, Ukraine is 1/4 the size of Russia by population, 1/8 by GDP. It is putting up a good fight like Imperial Japan did against the US. They're doomed to a slow loss by war of attrition since their heavy weapons and most of all, oil, isn't being replenished, just like Imperial Japan was, but they're doing OK.
But Vietnam? lol they were what, 1/10th US population, 1/50th by GDP? yet US lost 3000+ planes, 5000+ helicopters. Then tanks rolled into Saigon and it was all over.