Why did the Americans believe that the Cold War against communism was necessary? Please Help!?

Though cold was cannot be considered necessary, it had the advantage of stopping major powers just short of War. Capitalist system and Communism were opposed to each other and both tried to expand and also tried to prevent the other from expanding. A direct confrontation between the two systems got delayed as the result of the emergence of Nazism and Fascism.

Out of necessity US championing Capitalism and Russia championing communism joined to fight the Fascists. The defeat of the enemies was followed by efforts by Russia and the US to increase their spheres of influence in the conquered territories and caused a revival of their enmity and rivalry. This state of a condition of war without actual war was 'cold War'.

Past enmity made cold war inevitable and post-War situation made it difficult to start a direct hot war. The cold war any way served as a safety valve and saved the world form another major war.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.