They have the ability to kill billions of people with one atom bomb instead of one person at a time with a flintlock pistol
Answer:
the us tried to stop the spread of communism in Vietnam, it went badly because the Vietnam knew more area of land than the us did, resulting in unexpected attacks from the Vietnam. after quick attacks the Vietnam would retreat to the forest, where they had multiple bunkers that connected to one another so they could appear in multiple places in in a short amount of time.
Well, fear is created when there is a threat. WW2 Had just ended, so of course America did not want any other nation to become more powerful than them, for the idea that it would end up being like Germany. Americans also wanted to protect democracy, so communism was a major threat to the USA and it's beliefs. Naturally, America wanted to prove dominance to the USSR, thus the beginning of the cold war.
I don't have the proper answer and you might have to do research but America did gain much from the war such as Cuba, The Philipines, and Guam.