It would probably depend a lot on the type of conflict. The US would almost certainly have air-superiority, which would have a significant difference. Of course, air-superiority didn't "win" the US wars in Afghanistan or Iraq, but those were more guerilla-style wars with a somewhat (at least) hostile larger population. A US-Russia conflict would probably look pretty different. Or it would just go nuclear, in which case... well, so much for tactics.