Well in case of Poland i reckon if Russia would go against US (and while doing it against NATO) we would probably get invaded at this same time (well us and Russia have a lot of history toghether , plus we are neighbours) so yeah we probably would be fighting the sam war.
In case of Chinese Conflict i see as getting ivolved on US side as well (obviously to the extent that such country as Poland can) and i would probably support that Effort since at the end of the day America does stand for values that i think need to be defended.