People will inevitably have different desires that conflict, and they would prefer satisfying thier desires completely rather than considering the other's desires and coming to a compromise. Thats just human nature, and besides, humans are not naturally empathetic with people they dont personally know. Empathy like that is developed from experience. You dont believe me then look at the past.
On Topic: Theres going to be another major war inevitably imo, there always have been huge wars between major nations, and its probably not going to change anytime soon. Russia isn't too big a threat though I think, thier technology isn't as advanced as USA's, atleast thats what I've gatherd from watching tons of military shows (i love war technology). USA has obviously superior jets, superior tanks, and perhaps I'm prejudced but superior training too. Russia my try though to prove their not incompetent, but I think wil fail.. China would probably be the main threat for USA, but then again, their army has very little war experience, and if anyone remembers the Korean war, USA owned them despite having significantly smaller numbers.